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New Alps protocol in the wild?

DISCUSSION Ben Gamari 7 participants 21 messages Jul 27, 2012 – Sep 30, 2012 1 message not in the archive HID

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Ben Gamari

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#0 lore raw

Recently I took shipment of a Dell Latitude E6430 (supposedly "certified" by Canonical). Sadly, out of the box the multitouch-capable Alps Dualpoint mouse is detected as a generic PS/2 device (bug filed here[1]). After a bit of poking around I figured out the signature ({0x73, 0x03, 0x0a}) and command_mode_resp (0x1d) of the device.

Based on the other recent Dell models listed in alps_model_data, I tried configuring the device as a protocol v3 device. While in appearance the driver succeeded in configuring the device, it was clear that it was still operating in bare PS/2 mode (only bare PS/2 reports were received and 0x04 register was read to be 0x00 --- assuming the register read command is correct). This is supported by Seth's alps-reg-dump tool[2], which declares that the device is "Not a v3 ALPS touchpad". Trying to configure the device with protocol v4 resulted in the driver to fail during configuration (failing to enter absolute mode). Given this evidence, it seems fairly clear that this device differs appreciably from any device currently supported by alps.c.

I've tried to collect PS/2 traces from a Windows 7 installation running under a patched Qemu[3]. Unfortunately, while Windows running on bare hardware configures the device perfectly, an installation from the same media seems to treat the device as a bare PS/2 device when running under virtualization. The PS/2 trace produced clearly shows the driver probing the device as an Intellimouse and failing that falls back to generic PS/2 reports. Can anyone think of what might have changed between the bare metal and the virtualized environment?

I would love to take a stab at reversing this protocol variant, but the inability to get a trace from a virtualized working configuration is a real blocker. I suppose I could try writing a Windows filter driver but the virtualization approach seems orders of magnitude more convenient. Any ideas would be greatly appreciated.

As a final note, I have read various places that ALPS had intended on releasing a closed source driver for some of their devices. Has anything happened on this front? Perhaps it would be easier to get a trace from a closed-source driver running on Linux than a closed-source driver running on Windows.

Thanks again.

Cheers,

- Ben

[1] https://bugzilla.kernel.org/show_bug.cgi?id=45201
[2] http://kernel.ubuntu.com/git?p=sforshee/alps-reg-dump.git;a=summary
[3] http://swapspace.forshee.me/2011/11/touchpad-protocol-reverse-engineering.html

#1 lore raw
Quoted 6 lines · Ben Gamari

Recently I took shipment of a Dell Latitude E6430 (supposedly "certified" by Canonical). Sadly, out of the box the multitouch-capable Alps Dualpoint mouse is detected as a generic PS/2 device (bug filed here[1]). After a bit of poking around I figured out the signature ({0x73, 0x03, 0x0a}) and command_mode_resp (0x1d) of the device.

Quoted 11 lines

Based on the other recent Dell models listed in alps_model_data, I tried configuring the device as a protocol v3 device. While in appearance the driver succeeded in configuring the device, it was clear that it was still operating in bare PS/2 mode (only bare PS/2 reports were received and 0x04 register was read to be 0x00 --- assuming the register read command is correct). This is supported by Seth's alps-reg-dump tool[2], which declares that the device is "Not a v3 ALPS touchpad". Trying to configure the device with protocol v4 resulted in the driver to fail during configuration (failing to enter absolute mode). Given this evidence, it seems fairly clear that this device differs appreciably from any device currently supported by alps.c.

That's likely. It's known that there's at least one ALPS protocol version that isn't supported.

Quoted 8 lines

I've tried to collect PS/2 traces from a Windows 7 installation running under a patched Qemu[3]. Unfortunately, while Windows running on bare hardware configures the device perfectly, an installation from the same media seems to treat the device as a bare PS/2 device when running under virtualization. The PS/2 trace produced clearly shows the driver probing the device as an Intellimouse and failing that falls back to generic PS/2 reports. Can anyone think of what might have changed between the bare metal and the virtualized environment?

I'm thinking that when I was looking at the initialization from Windows drivers it would first initialize it like a normal PS/2 mouse then later the ALPS initialization would show up, almost like the default driver ran through it's initialization first before the ALPS driver did. Did you look further down in the logs to see if anything similar to the ALPS initialization is happening later?

Otherwise I don't have any ideas off the top of my head. This approach generally worked fine with the machines/drivers I worked with.

Quoted 11 lines

I would love to take a stab at reversing this protocol variant, but the inability to get a trace from a virtualized working configuration is a real blocker. I suppose I could try writing a Windows filter driver but the virtualization approach seems orders of magnitude more convenient. Any ideas would be greatly appreciated.

As a final note, I have read various places that ALPS had intended on releasing a closed source driver for some of their devices. Has anything happened on this front? Perhaps it would be easier to get a trace from a closed-source driver running on Linux than a closed-source driver running on Windows.

I've heard that such a driver exists, but I don't know where you can get it. I _think_ some factory preinstalled Linux systems might ship with it, so it's possible that it's something ALPS provides to its customers but doesn't make publicly available.

Cheers,
Seth

author
#2 lore raw
Quoted 19 lines · Seth Forshee
Quoted 6 lines · Ben Gamari

Recently I took shipment of a Dell Latitude E6430 (supposedly "certified" by Canonical). Sadly, out of the box the multitouch-capable Alps Dualpoint mouse is detected as a generic PS/2 device (bug filed here[1]). After a bit of poking around I figured out the signature ({0x73, 0x03, 0x0a}) and command_mode_resp (0x1d) of the device.

Quoted 11 lines

Based on the other recent Dell models listed in alps_model_data, I tried configuring the device as a protocol v3 device. While in appearance the driver succeeded in configuring the device, it was clear that it was still operating in bare PS/2 mode (only bare PS/2 reports were received and 0x04 register was read to be 0x00 --- assuming the register read command is correct). This is supported by Seth's alps-reg-dump tool[2], which declares that the device is "Not a v3 ALPS touchpad". Trying to configure the device with protocol v4 resulted in the driver to fail during configuration (failing to enter absolute mode). Given this evidence, it seems fairly clear that this device differs appreciably from any device currently supported by alps.c.

Quoted 3 lines

That's likely. It's known that there's at least one ALPS protocol version that isn't supported.

I suspected that was the case.

Quoted 9 lines
Quoted 8 lines

I've tried to collect PS/2 traces from a Windows 7 installation running under a patched Qemu[3]. Unfortunately, while Windows running on bare hardware configures the device perfectly, an installation from the same media seems to treat the device as a bare PS/2 device when running under virtualization. The PS/2 trace produced clearly shows the driver probing the device as an Intellimouse and failing that falls back to generic PS/2 reports. Can anyone think of what might have changed between the bare metal and the virtualized environment?

Quoted 7 lines

I'm thinking that when I was looking at the initialization from Windows drivers it would first initialize it like a normal PS/2 mouse then later the ALPS initialization would show up, almost like the default driver ran through it's initialization first before the ALPS driver did. Did you look further down in the logs to see if anything similar to the ALPS initialization is happening later?

Sadly no. The driver comes with a configuration tool which when launched appears to trigger a reconfiguration.

Quoted 3 lines

Otherwise I don't have any ideas off the top of my head. This approach generally worked fine with the machines/drivers I worked with.

Hmmm, that is truly unfortunate. I guess given this I'll just have to try piecing together a filter driver and collect the initialization process on bare metal. Hopefully at that point I'll be able to do the reversing of the data format over serio.

Quoted 12 lines
Quoted 11 lines

I would love to take a stab at reversing this protocol variant, but the inability to get a trace from a virtualized working configuration is a real blocker. I suppose I could try writing a Windows filter driver but the virtualization approach seems orders of magnitude more convenient. Any ideas would be greatly appreciated.

As a final note, I have read various places that ALPS had intended on releasing a closed source driver for some of their devices. Has anything happened on this front? Perhaps it would be easier to get a trace from a closed-source driver running on Linux than a closed-source driver running on Windows.

Quoted 5 lines

I've heard that such a driver exists, but I don't know where you can get it. I _think_ some factory preinstalled Linux systems might ship with it, so it's possible that it's something ALPS provides to its customers but doesn't make publicly available.

Naturally. I never would have suspected that such a despicable company could be found in making something as innocuous as touchpads. Sheesh.

Given the difficulty of the reverse engineering process and the proliferation of incompatible hardware variants, it seems a major customer really needs to step up and demand some sanity from these people. My understanding is that Dell currently does not have access to Alps specifications but given the volume they move it seems they are in a fairly unique position to exert pressure. Being a Dell partner, has Canonical taken any steps to start this dialogue?

On that note, Canonical's certification certificate for the E6430 is currently incorrect. The desktop program guidelines clearly state that vertical scroll is on the grey list yet, as far as I can tell, the certificate makes no mention of the lacking support of the input hardware of this model.

Cheers,

- Ben

#3 lore raw

Coming late the discussion, responses inline - Dave

Quoted 20 lines · Ben Gamari
Quoted 18 lines · Seth Forshee
Quoted 17 lines · Ben Gamari

Recently I took shipment of a Dell Latitude E6430 (supposedly "certified" by Canonical). Sadly, out of the box the multitouch-capable Alps Dualpoint mouse is detected as a generic PS/2 device (bug filed here[1]). After a bit of poking around I figured out the signature ({0x73, 0x03, 0x0a}) and command_mode_resp (0x1d) of the device.

Based on the other recent Dell models listed in alps_model_data, I tried configuring the device as a protocol v3 device. While in appearance the driver succeeded in configuring the device, it was clear that it was still operating in bare PS/2 mode (only bare PS/2 reports were received and 0x04 register was read to be 0x00 --- assuming the register read command is correct). This is supported by Seth's alps-reg-dump tool[2], which declares that the device is "Not a v3 ALPS touchpad". Trying to configure the device with protocol v4 resulted in the driver to fail during configuration (failing to enter absolute mode). Given this evidence, it seems fairly clear that this device differs appreciably from any device currently supported by alps.c.

Quoted 4 lines
Quoted 3 lines

That's likely. It's known that there's at least one ALPS protocol version that isn't supported.

I suspected that was the case.

I have a Dell I15R N5110 running Ubuntu 12.04 with the same signature and behavior.

Vbox with sforshee patch running Vista shows only ps/2 packets. I hypothesized that the Vista driver didn't recognize the device either, but handled keyboard/touchpad event separation better.

I wrote a small serio_raw program to test the device. Alps command mode works, but the GETINFO response when entering command mode is: 0x73, 0x01, 0x0d, which fails the 0x88, 0x07 check in the alps.c code. Once in command mode, the v3 logic (PSMOUSE_CMD_RESET_WRAP) works and I get the register number and value back from PSMOUSE_CMD_GETINFO. v4 logic returns garbage.

Quoted 18 lines
Quoted 8 lines
Quoted 8 lines

I've tried to collect PS/2 traces from a Windows 7 installation running under a patched Qemu[3]. Unfortunately, while Windows running on bare hardware configures the device perfectly, an installation from the same media seems to treat the device as a bare PS/2 device when running under virtualization. The PS/2 trace produced clearly shows the driver probing the device as an Intellimouse and failing that falls back to generic PS/2 reports. Can anyone think of what might have changed between the bare metal and the virtualized environment?

Quoted 7 lines

I'm thinking that when I was looking at the initialization from Windows drivers it would first initialize it like a normal PS/2 mouse then later the ALPS initialization would show up, almost like the default driver ran through it's initialization first before the ALPS driver did. Did you look further down in the logs to see if anything similar to the ALPS initialization is happening later?

Sadly no. The driver comes with a configuration tool which when launched appears to trigger a reconfiguration.

Quoted 7 lines
Quoted 3 lines

Otherwise I don't have any ideas off the top of my head. This approach generally worked fine with the machines/drivers I worked with.

Hmmm, that is truly unfortunate. I guess given this I'll just have to try piecing together a filter driver and collect the initialization process on bare metal. Hopefully at that point I'll be able to do the reversing of the data format over serio.

Yeah, unfortunate. I may just use a usb mouse if it comes to that...

Quoted 28 lines
Quoted 12 lines
Quoted 7 lines

I would love to take a stab at reversing this protocol variant, but the inability to get a trace from a virtualized working configuration is a real blocker. I suppose I could try writing a Windows filter driver but the virtualization approach seems orders of magnitude more convenient. Any ideas would be greatly appreciated.

Quoted 5 lines

As a final note, I have read various places that ALPS had intended on releasing a closed source driver for some of their devices. Has anything happened on this front? Perhaps it would be easier to get a trace from a closed-source driver running on Linux than a closed-source driver running on Windows.

Quoted 5 lines

I've heard that such a driver exists, but I don't know where you can get it. I _think_ some factory preinstalled Linux systems might ship with it, so it's possible that it's something ALPS provides to its customers but doesn't make publicly available.

Naturally. I never would have suspected that such a despicable company could be found in making something as innocuous as touchpads. Sheesh.

Given the difficulty of the reverse engineering process and the proliferation of incompatible hardware variants, it seems a major customer really needs to step up and demand some sanity from these people. My understanding is that Dell currently does not have access to Alps specifications but given the volume they move it seems they are in a fairly unique position to exert pressure. Being a Dell partner, has Canonical taken any steps to start this dialogue?

Quoted 5 lines

On that note, Canonical's certification certificate for the E6430 is currently incorrect. The desktop program guidelines clearly state that vertical scroll is on the grey list yet, as far as I can tell, the certificate makes no mention of the lacking support of the input hardware of this model.

My I15R was certified also, and currently incorrect. I posted a query to Dell about Alps support but haven't heard anything back. I suspect Alps and Dell are wary of offending Microsoft.

Quoted 10 lines

Cheers,

- Ben

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#4 lore raw

[ Dmitry should be CCed on this ... adding him ]

Quoted 109 lines · dturvene

Coming late the discussion, responses inline - Dave

Quoted 20 lines · Ben Gamari
Quoted 18 lines · Seth Forshee
Quoted 17 lines · Ben Gamari

Recently I took shipment of a Dell Latitude E6430 (supposedly "certified" by Canonical). Sadly, out of the box the multitouch-capable Alps Dualpoint mouse is detected as a generic PS/2 device (bug filed here[1]). After a bit of poking around I figured out the signature ({0x73, 0x03, 0x0a}) and command_mode_resp (0x1d) of the device.

Based on the other recent Dell models listed in alps_model_data, I tried configuring the device as a protocol v3 device. While in appearance the driver succeeded in configuring the device, it was clear that it was still operating in bare PS/2 mode (only bare PS/2 reports were received and 0x04 register was read to be 0x00 --- assuming the register read command is correct). This is supported by Seth's alps-reg-dump tool[2], which declares that the device is "Not a v3 ALPS touchpad". Trying to configure the device with protocol v4 resulted in the driver to fail during configuration (failing to enter absolute mode). Given this evidence, it seems fairly clear that this device differs appreciably from any device currently supported by alps.c.

Quoted 4 lines
Quoted 3 lines

That's likely. It's known that there's at least one ALPS protocol version that isn't supported.

I suspected that was the case.

I have a Dell I15R N5110 running Ubuntu 12.04 with the same signature and behavior.

Vbox with sforshee patch running Vista shows only ps/2 packets. I hypothesized that the Vista driver didn't recognize the device either, but handled keyboard/touchpad event separation better.

I wrote a small serio_raw program to test the device. Alps command mode works, but the GETINFO response when entering command mode is: 0x73, 0x01, 0x0d, which fails the 0x88, 0x07 check in the alps.c code. Once in command mode, the v3 logic (PSMOUSE_CMD_RESET_WRAP) works and I get the register number and value back from PSMOUSE_CMD_GETINFO. v4 logic returns garbage.

Quoted 19 lines
Quoted 9 lines
Quoted 9 lines

I've tried to collect PS/2 traces from a Windows 7 installation running under a patched Qemu[3]. Unfortunately, while Windows running on bare hardware configures the device perfectly, an installation from the same media seems to treat the device as a bare PS/2 device when running under virtualization. The PS/2 trace produced clearly shows the driver probing the device as an Intellimouse and failing that falls back to generic PS/2 reports. Can anyone think of what might have changed between the bare
metal and the virtualized environment?

Quoted 7 lines

I'm thinking that when I was looking at the initialization from Windows drivers it would first initialize it like a normal PS/2 mouse then later the ALPS initialization would show up, almost like the default driver ran through it's initialization first before the ALPS driver did. Did you look further down in the logs to see if anything similar to the ALPS initialization is happening later?

Sadly no. The driver comes with a configuration tool which when launched appears to trigger a reconfiguration.

Quoted 7 lines
Quoted 3 lines

Otherwise I don't have any ideas off the top of my head. This approach generally worked fine with the machines/drivers I worked with.

Hmmm, that is truly unfortunate. I guess given this I'll just have to try piecing together a filter driver and collect the initialization process on bare metal. Hopefully at that point I'll be able to do the reversing of the data format over serio.

Yeah, unfortunate. I may just use a usb mouse if it comes to that...

Quoted 28 lines
Quoted 12 lines
Quoted 7 lines

I would love to take a stab at reversing this protocol variant, but the inability to get a trace from a virtualized working configuration is a real blocker. I suppose I could try writing a Windows filter driver but the virtualization approach seems orders of magnitude more convenient. Any ideas would be greatly appreciated.

Quoted 5 lines

As a final note, I have read various places that ALPS had intended on releasing a closed source driver for some of their devices. Has anything happened on this front? Perhaps it would be easier to get a trace from a closed-source driver running on Linux than a closed-source driver running on Windows.

Quoted 5 lines

I've heard that such a driver exists, but I don't know where you can get it. I _think_ some factory preinstalled Linux systems might ship with it, so it's possible that it's something ALPS provides to its customers but doesn't make publicly available.

Naturally. I never would have suspected that such a despicable company could be found in making something as innocuous as touchpads. Sheesh.

Given the difficulty of the reverse engineering process and the proliferation of incompatible hardware variants, it seems a major customer really needs to step up and demand some sanity from these people. My understanding is that Dell currently does not have access to Alps specifications but given the volume they move it seems they are in a fairly unique position to exert pressure. Being a Dell partner, has Canonical taken any steps to start this dialogue?

Quoted 5 lines

On that note, Canonical's certification certificate for the E6430 is currently incorrect. The desktop program guidelines clearly state that vertical scroll is on the grey list yet, as far as I can tell, the certificate makes no mention of the lacking support of the input hardware of this model.

My I15R was certified also, and currently incorrect. I posted a query to Dell about Alps support but haven't heard anything back. I suspect Alps and Dell are wary of offending Microsoft.

Quoted 4 lines

Cheers,

- Ben

Signature · 2 lines
Jiri Kosina
SUSE Labs
author
#5 lore raw
In reply to Ben Gamari

Just to keep everyone in the loop, I've tried both VirtualBox and Qemu now and the Alps driver appears to work under neither. After some reflection, I finally resolved to brave the jungle that is Windows driver development and now have the beginnings of a PS/2 filter driver[1]. It's quite hacked together and is likely a textbook example of how not to write a Windows driver, but it's nearly working. That being said, if anyone has experience with NT kernel development, feel free to assist in any way you can.

That being said, I'd recommend you don't install it at the moment; it currently BSODs from use of DebugPrint in an ISR. Before breaking it, however, I was able to get incoming data from the trackpad. The breaking changes were an attempt to gather outgoing commands to the device so I'm (hopefully) not far from having traces.

Cheers,

- Ben

[1] https://github.com/bgamari/ps2log

author
#6 lore raw
Quoted 9 lines · Ben Gamari

Just to keep everyone in the loop, I've tried both VirtualBox and Qemu now and the Alps driver appears to work under neither. After some reflection, I finally resolved to brave the jungle that is Windows driver development and now have the beginnings of a PS/2 filter driver[1]. It's quite hacked together and is likely a textbook example of how not to write a Windows driver, but it's nearly working. That being said, if anyone has experience with NT kernel development, feel free to assist in any way you can.

Quoted 6 lines

That being said, I'd recommend you don't install it at the moment; it currently BSODs from use of DebugPrint in an ISR. Before breaking it, however, I was able to get incoming data from the trackpad. The breaking changes were an attempt to gather outgoing commands to the device so I'm (hopefully) not far from having traces.

Sadly, this avenue of investigation is apparently a dead-end. After seeing nothing outbound to the mouse and hacking around enough to convince myself that filter driver is catching all traffic passed through the i8042prt driver, I finally decided to disassemble apfiltr.sys. Perhaps not unexpectedly, it seems they do some direct port I/O without going through the driver stack. Whether this is incompetance or malice we will never know, but it seems that the "clean" filter driver approach will not work here.

Thankfully, it seems that an I/O port sniffer driver[1] has been written which might save me. Sadly, this isn't supported on 64-bit machines as Microsoft's compiler inexplicably lacks support for inline assembler on amd64. I've found a 32-bit copy of Vista lying around so we'll see how this works.

Of course, if anyone has any idea what might be breaking the virtualization approach, I'd love to hear. Moreover, if anyone knows someone (at Dell or elsewhere) who might be able to get a hold of an ear at Alps, this would be greatly appreciated.

Cheers,

- Ben

[1] http://www.codeproject.com/Articles/96142/I-O-port-sniffer

#7 lore raw
Quoted 26 lines · Ben Gamari
Quoted 9 lines · Ben Gamari

Just to keep everyone in the loop, I've tried both VirtualBox and Qemu now and the Alps driver appears to work under neither. After some reflection, I finally resolved to brave the jungle that is Windows driver development and now have the beginnings of a PS/2 filter driver[1]. It's quite hacked together and is likely a textbook example of how not to write a Windows driver, but it's nearly working. That being said, if anyone has experience with NT kernel development, feel free to assist in any way you can.

Quoted 6 lines

That being said, I'd recommend you don't install it at the moment; it currently BSODs from use of DebugPrint in an ISR. Before breaking it, however, I was able to get incoming data from the trackpad. The breaking changes were an attempt to gather outgoing commands to the device so I'm (hopefully) not far from having traces.

Sadly, this avenue of investigation is apparently a dead-end. After seeing nothing outbound to the mouse and hacking around enough to convince myself that filter driver is catching all traffic passed through the i8042prt driver, I finally decided to disassemble apfiltr.sys. Perhaps not unexpectedly, it seems they do some direct port I/O without going through the driver stack. Whether this is incompetance or malice we will never know, but it seems that the "clean" filter driver approach will not work here.

Quoted 8 lines

Thankfully, it seems that an I/O port sniffer driver[1] has been written which might save me. Sadly, this isn't supported on 64-bit machines as Microsoft's compiler inexplicably lacks support for inline assembler on amd64. I've found a 32-bit copy of Vista lying around so we'll see how this works.

Of course, if anyone has any idea what might be breaking the virtualization approach, I'd love to hear.

Given how unwilling they are to share details of their protocol I would not be surprised if they tried to detect virtual environment on purpose.

Thanks.

Signature · 1 line
Dmitry
author
#8 lore raw
Quoted 3 lines · Dmitry Torokhov

Given how unwilling they are to share details of their protocol I would not be surprised if they tried to detect virtual environment on purpose.

Sadly, you very well could be right.

That being said, I don't know what they could be checking for. I'm passing "-cpu host" to qemu which should eliminate the CPUID hint. Otherwise, the only obvious hint I can find is the hard drive which mentions Qemu in its vendor string. Taking a quick look at the apfiltr.sys I can't find any strings that might imply it's looking at device/vendor strings. Perhaps they could be using ACPI tables (although I see no ACPI-ish strings in the driver)? I guess SMBIOS and DMI are also targets although I know little about their implementation.

Anyways, I suppose at this point it is probably time to bring this discussion over to the qemu list to discuss future directions for virtualization. Unfortunately, it becomes very difficult to maintain motivation on problems like this when Alps will likely render whatever reverse engineering knowledge gained now obsolete in the next iteration of hardware. It seems clear that the only sustainable way to get open-source support for these and future Alps devices is with some cooperation from Alps and/or a major customer. It seems that Dell is in an ideal position to help here.

Cheers,

- Ben

author
#9 lore raw
In reply to Ben Gamari
Quoted 9 lines · Ben Gamari

Sadly, this avenue of investigation is apparently a dead-end. After seeing nothing outbound to the mouse and hacking around enough to convince myself that filter driver is catching all traffic passed through the i8042prt driver, I finally decided to disassemble apfiltr.sys. Perhaps not unexpectedly, it seems they do some direct port I/O without going through the driver stack. Whether this is incompetance or malice we will never know, but it seems that the "clean" filter driver approach will not work here.

Quoted 6 lines

Thankfully, it seems that an I/O port sniffer driver[1] has been written which might save me. Sadly, this isn't supported on 64-bit machines as Microsoft's compiler inexplicably lacks support for inline assembler on amd64. I've found a 32-bit copy of Vista lying around so we'll see how this works.

Unfortunately, it seems that this approach too may be a dead end. The iosniffer driver appears to cause an immediate reboot (triple fault?) on installing its hooks. Given the low-level nature of the crash, the thought of tracking it down makes me shudder. If anyone else wants to try installing the driver, it would be nice to have a second opinion. I guess it's back to the virtualization approach.

Cheers,

- Ben

#10 lore raw
In reply to Ben Gamari

I just got a Dell E6230 with the same E7 report: 73 03 0a As noted above using the qemu serio logging doesn't work. The driver only enables multitouch if it sees the right name for the device in the DSDT.

The following patch (against the seabios in qemu-0.14.1) enables the windows 7 driver (7.1211.101.114 from
http://www.dell.com/support/drivers/us/en/04/DriverDetails/DriverFileFormats/Product/latitude-e6230?DriverId=CKNFN&FileId=2988050063&urlProductCode=False
) to bind successfully and alows one to get data from the serio logging patch

Are there any standard tools for reverse engineering the protocol - I saw mention of an alps-reg-dump but was unable to find it?

thanks,

James.

qemu-0.14.1.jmm/roms/seabios/src/acpi-dsdt.dsl renamed from qemu-0.14.1/roms/seabios/src/acpi-dsdt.dsl +40 -20
@@ -253,7 +253,7 @@
             }
 
             /* Keyboard seems to be important for WinXP install */
-            Device (KBD)
+            Device (PS2K)
             {
                 Name (_HID, EisaId ("PNP0303"))
                 Method (_STA, 0, NotSerialized)
@@ -261,10 +261,8 @@
                     Return (0x0f)
                 }
 
-                Method (_CRS, 0, NotSerialized)
+		Name (_CRS, ResourceTemplate ()
                 {
-                     Name (TMP, ResourceTemplate ()
-                     {
                     IO (Decode16,
                         0x0060,             // Address Range Minimum
                         0x0060,             // Address Range Maximum
@@ -277,30 +275,52 @@
                         0x01,               // Address Alignment
                         0x01,               // Address Length
                         )
+                IRQ (Edge, ActiveHigh, Exclusive, )
+                    {1}
+
+                })
+
+
+
+
+            Name (_PRS, ResourceTemplate ()
+            {
+                StartDependentFn (0x00, 0x00)
+                {
+                    FixedIO (
+                        0x0060,             // Address
+                        0x01,               // Length
+                        )
+                    FixedIO (
+                        0x0064,             // Address
+                        0x01,               // Length
+                        )
                     IRQNoFlags ()
                         {1}
-                    })
-                    Return (TMP)
                 }
-            }
+                EndDependentFn ()
+            })
+		}
 
 	    /* PS/2 mouse */
-            Device (MOU)
+            Device (PS2M)
             {
-                Name (_HID, EisaId ("PNP0F13"))
-                Method (_STA, 0, NotSerialized)
-                {
-                    Return (0x0f)
-                }
-
-                Method (_CRS, 0, NotSerialized)
+                Name (_CID, EisaId ("PNP0F13"))
+		Name (_HID, EisaId ("DLL0532"))
+            Name (_CRS, ResourceTemplate ()
+            {
+                IRQ (Edge, ActiveHigh, Exclusive, )
+                    {12}
+            })
+            Name (_PRS, ResourceTemplate ()
+            {
+                StartDependentFn (0x00, 0x00)
                 {
-                    Name (TMP, ResourceTemplate ()
-                    {
-                         IRQNoFlags () {12}
-                    })
-                    Return (TMP)
+                    IRQNoFlags ()
+                        {12}
                 }
+                EndDependentFn ()
+            })
             }
 
 	    /* PS/2 floppy controller */
#11 lore raw
Quoted 11 lines · James

I just got a Dell E6230 with the same E7 report: 73 03 0a As noted above using the qemu serio logging doesn't work. The driver only enables multitouch if it sees the right name for the device in the DSDT.

The following patch (against the seabios in qemu-0.14.1) enables the windows 7 driver (7.1211.101.114 from
http://www.dell.com/support/drivers/us/en/04/DriverDetails/DriverFileFormats/Product/latitude-e6230?DriverId=CKNFN&FileId=2988050063&urlProductCode=False
) to bind successfully and alows one to get data from the serio logging patch

Quoted 4 lines

Are there any standard tools for reverse engineering the protocol - I saw mention of an alps-reg-dump but was unable to find it?

alps-reg-dump can be found here[1]. Depending upon how different the protocol is it may or may not be useful, however.

Cheers,

- Ben

[1] http://kernel.ubuntu.com/git?p=sforshee/alps-reg-dump.git;a=summary

#12 lore raw
Quoted 13 lines · Ben Gamari
Quoted 11 lines · James

I just got a Dell E6230 with the same E7 report: 73 03 0a As noted above using the qemu serio logging doesn't work. The driver only enables multitouch if it sees the right name for the device in the DSDT.

The following patch (against the seabios in qemu-0.14.1) enables the windows 7 driver (7.1211.101.114 from
http://www.dell.com/support/drivers/us/en/04/DriverDetails/DriverFileFormats/Product/latitude-e6230?DriverId=CKNFN&FileId=2988050063&urlProductCode=False
) to bind successfully and alows one to get data from the serio logging patch

Quoted 6 lines
Quoted 4 lines

Are there any standard tools for reverse engineering the protocol - I saw mention of an alps-reg-dump but was unable to find it?

alps-reg-dump can be found here[1]. Depending upon how different the protocol is it may or may not be useful, however.

Just a warning that I haven't updated that in quite some time, and I'm not even sure exactly how far I was in reverse engineering the protocol when I stopped updating it. So it may or may not be useful to you.

Seth

author
#13 lore raw
In reply to James

After doing some fiddling around myself, I've put together a few tools and I think I now have the beginnings of an understanding of the report frame structure. I've attached some notes below. The data packets appear to be 6 bytes long, consistent with earlier versions of the protocol. The first and fifth bytes of the touchpad packet are still quite mysterious. While they likely have something to do with multitouch, they both fluctuate even with single touch events. Touchpad packets can be distinguished from stick packets by examining the byte 5, which is 0x3f (out of the range of the pressure field) in touchstick packets.

I've also attached two tools I've developed. ps2-parse.py annotates PS/2 traces produced by the VM with common command names (simply pipe a trace in to stdin, out comes the annotate trace on stdout). Alps.py is a first attempt at communicating with the hardware. It currently has the ability to put playback a trace (say, the attached serio-init.log) and start dumping frames to stdout. It also has an incomplete version of the initialization sequence (enter_absolute_mode).

Hopefully I'll find some more time in the next few days to figure out the last few bits (primarily how multitouch events work). I wouldn't be sad if someone finished the task for me, however.

Cheers,

- Ben

Touchpad Packet format:
byte 0: ??? starts with 0x9f, 0x8f, changes

          0x10:  ??
          0x20:  ??
          0x8f:  Always set
          Only 0x10 and 0x20 are set with single-touch events. 0x40 seems to be set with multitouch events

byte 1: X position? (- is left, + is right)
byte 2: Y position? (- is up, + is down)
byte 3: button state:

                0x1:  left touchpad
                0x2:  right touchpad
                0x4:  middle touchpad?
                0x8:  Always set?
                0x10: left touchstick
                0x20: right touchstick
                0x40: middle touchstick
                0x80: ???
  byte 4: ???
  byte 5: Pressure (0x00 - 0x3e)
                0x3f: Reporting stick?

Touchstick Packet format:

  byte 0: 0x10:  Y Sign
          0x20:  X Sign
          0x4f:  Always set

byte 1: X pressure (0 - 0x7f)
byte 2: Y pressure (0 - 0x7f)
byte 3: always 0x48
byte 4: Z pressure (0 - 0x7c)
byte 5: always 0x3f

#!/usr/bin/python3.2

import sys
from glob import glob
from time import sleep
import logging

logging.basicConfig(level=logging.DEBUG)

def find_serio_device():

        for f in glob('/sys/bus/serio/devices/serio*'):
                a = open('%s/description'%f).read()
                if 'i8042 AUX' in a:
                        return f

#dev = find_serio_device()
#logging.info("Found device %s" % dev)
#open('%s/drvctl'%dev, 'w').write('serio_raw')
#sleep(1)

serio_dev = sys.argv[1]
#serio_dev = glob('/dev/serio*')[0]
f = open(serio_dev, 'wb+')

def playback(cmds):

        for dir,data in cmds:
                if dir == 'S':
                        logging.debug('Sent %02x' % data)
                        f.write(bytes([data]))
                elif dir == 'R':
                        a = f.read(1)
                        logging.debug('Recieved %02x' % a[0])
                        if data != a[0]:
                                logging.warn('reply mismatch: expected %02x, saw %02x' % (data, a[0]))
                else:
                        raise RuntimeError("uh oh")

def recv_ack():

        a = b''
        logging.debug('Waiting for ACK')
        while len(a) == 0:
                a = f.read(1)
        print(len(a))
        if a != b'\xfa':
                raise RuntimeError("oops: %s" % str(a))

def reset():

        f.write(b'\xff')
        recv_ack()
        a = f.read(2)
        return a

def get_device_id():

        f.write(b'\xf2')
        recv_ack()
        a = f.read(1)
        return a

def set_resolution(arg):

        f.write(b'\xe8')
        recv_ack()
        f.write(arg)
        recv_ack()

def set_sample_rate(arg):

        f.write(b'\xf3')
        recv_ack()
        f.write(arg)
        recv_ack()

def set_1_1_scaling():

        f.write(b'\xe6')
        recv_ack()

def status_rq():

        f.write(b'\xe9')
        recv_ack()
        a = f.read(3)
        return a

def enable_data_reporting():

        f.write(b'\xf4')
        recv_ack()

def disable_data_reporting():

        f.write(b'\xf5')
        recv_ack()

def enter_absolute_mode():

        reset()
        reset()
        get_device_id()
        set_resolution(b'\x00')
        set_1_1_scaling()
        set_1_1_scaling()
        set_1_1_scaling()
        status_rq()
        set_resolution(b'\x03')
        set_sample_rate(b'\xc8')
        set_sample_rate(b'\x64')
        set_sample_rate(b'\x50')
        get_device_id()
        set_sample_rate(b'\xc8')
        set_sample_rate(b'\xc8')
        set_sample_rate(b'\x50')
        set_resolution(b'\x03')
        enable_data_reporting()

def format_bytes(bytes):

        return map(lambda b: '%02x' % b, bytes)

cmds = []
for l in open('serio-init.log'):

        (dir,data) = (l[0], int(l[1:4], 16))
        cmds.append((dir,data))

disable_data_reporting()
reset()
reset()
playback(cmds)

#enter_absolute_mode()
try:

        while True:
                a = f.read(6)
                print('  '.join(format_bytes(a)))

except KeyboardInterrupt:
pass

#open('%s/drvctl'%dev, 'w').write('psmouse')

#!/usr/bin/python

import sys

def get_line():
l = sys.stdin.readline()
return (l[0], int(l[1:], 16))

def get_ack():

        (dir,data) = get_line()
        if dir!='R' and data!=0xfa:
                print('! Unknown reply: %02x'%data)

while True:

        notes = ''
        (dir,data) = get_line()
        if dir == 'S':
                get_ack()
                if data == 0xff:
                        notes = 'reset'
                elif data == 0xfe:
                        notes = 'resend'
                elif data == 0xf6:
                        notes = 'set defaults'
                elif data == 0xf5:
                        notes = 'disable reporting'
                elif data == 0xf4:
                        notes = 'enable reporting'
                elif data == 0xf3:
                        dir,data = get_line()
                        notes = 'set_sample_rate: %02x' % data
                        get_ack()
                elif data == 0xf2:
                        _,d = get_line()
                        notes = 'get device id: %02x' % d
                elif data == 0xf0:
                        notes = 'set remote mode'
                elif data == 0xee:
                        notes = 'set wrap mode'
                elif data == 0xec:
                        notes = 'reset wrap mode'
                elif data == 0xeb:
                        notes = 'read data'
                elif data == 0xea:
                        notes = 'set stream mode'
                elif data == 0xe9:
                        _,d1 = get_line()
                        _,d2 = get_line()
                        _,d3 = get_line()
                        notes = 'status request: %02x  resolution=%02x  rate=%02x' % (d1, d2, d3)
                elif data == 0xe8:
                        _,d = get_line()
                        notes = 'set resolution: %02x' % d
                        get_ack()
                elif data == 0xe7:
                        notes = 'set scaling 2:1'
                elif data == 0xe6:
                        notes = 'set scaling 1:1'
                else:
                        notes = 'unknown command'


        print('%s %02x     %s' % (dir, data, notes))

S ff
R fa
R aa
R 00
S ff
R fa
R aa
R 00
S f2
R fa
R 00
S e8
R fa
S 00
R fa
S e6
R fa
S e6
R fa
S e6
R fa
S e9
R fa
R 00
R 00
R 64
S e8
R fa
S 03
R fa
S f3
R fa
S c8
R fa
S f3
R fa
S 64
R fa
S f3
R fa
S 50
R fa
S f2
R fa
R 00
S f3
R fa
S c8
R fa
S f3
R fa
S c8
R fa
S f3
R fa
S 50
R fa
S f2
R fa
R 00
S f3
R fa
S 64
R fa
S e8
R fa
S 03
R fa
S f4
R fa
S f5
R fa
S ff
R fa
R aa
R 00
S e7
R fa
S e7
R fa
S e7
R fa
S e9
R fa
R 73
R 03
R 0a
S ea
R fa
S ec
R fa
S ec
R fa
S ec
R fa
S e9
R fa
R 88
R 08
R 1d
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 64
R fa
S e9
R fa
R c2
R c8
R 80
S f3
R fa
S 64
R fa
S f6
R fa
S ea
R fa
S e7
R fa
S e7
R fa
S e7
R fa
S e9
R fa
R 42
R 02
R 3c
S e6
R fa
S e6
R fa
S e6
R fa
S f3
R fa
S c8
R fa
S f3
R fa
S 14
R fa
S ea
R fa
S ec
R fa
S ec
R fa
S ec
R fa
S e9
R fa
R 88
R 08
R 1d
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 64
R fa
S f3
R fa
S 64
R fa
S e7
R fa
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 14
R fa
S e9
R fa
R c2
R c4
R 00
S f0
R fa
S e7
R fa
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 02
R fa
S f3
R fa
S c8
R fa
S e9
R fa
R c2
R d9
R 00
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S e8
R fa
S 00
R fa
S f0
R fa
S f0
R fa
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 64
R fa
S e9
R fa
R c2
R c8
R 82
S f3
R fa
S 64
R fa
S e7
R fa
S ea
R fa
S f3
R fa
S 64
R fa
S f4
R fa
S f5
R fa
S ff
R fa
R aa
S f5
S ff
R fa
R fa
R aa
R 00
S e7
R fa
S e7
R fa
S e7
R fa
S e9
R fa
R 73
R 03
R 0a
S ea
R fa
S ec
R fa
S ec
R fa
S ec
R fa
S e9
R fa
R 88
R 08
R 1d
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 64
R fa
S e9
R fa
R c2
R c8
R 80
S f3
R fa
S 64
R fa
S f6
R fa
S ea
R fa
S e7
R fa
S e7
R fa
S e7
R fa
S e9
R fa
R 42
R 02
R 3c
S e6
R fa
S e6
R fa
S e6
R fa
S f3
R fa
S c8
R fa
S f3
R fa
S 14
R fa
S ea
R fa
S ec
R fa
S ec
R fa
S ec
R fa
S e9
R fa
R 88
R 08
R 1d
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 64
R fa
S f3
R fa
S 64
R fa
S e7
R fa
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 14
R fa
S e9
R fa
R c2
R c4
R 00
S f0
R fa
S e7
R fa
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 02
R fa
S f3
R fa
S c8
R fa
S e9
R fa
R c2
R d9
R 00
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S e8
R fa
S 00
R fa
S f0
R fa
S f0
R fa
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 64
R fa
S e9
R fa
R c2
R c8
R 82
S f3
R fa
S 64
R fa
S e7
R fa
S ea
R fa
S f3
R fa
S 64
R fa
S f4
R fa
S f5
R fa
S f2
R fa
R 00
S ea
R fa
S ec
R fa
S ec
R fa
S ec
R fa
S e9
R fa
R 88
R 08
R 1d
S ec
R fa
S e8
R fa
S 01
R fa
S e7
R fa
S e8
R fa
S 01
R fa
S f3
R fa
S 28
R fa
S e9
R fa
R c2
R c5
R 69
S f3
R fa
S 3c
R fa
S f3
R fa
S c8
R fa
S ea
R fa
S f4
R fa

author
#14 lore raw

Ben Gamari <[email protected]> writes:

snip

Quoted 5 lines

Hopefully I'll find some more time in the next few days to figure out the last few bits (primarily how multitouch events work). I wouldn't be sad if someone finished the task for me, however.

Success! As it turns out, the process was actually not so bad. While I wasted much of the night trying to reverse the protocol, I realized that what I had come up with was nearly identical to the version 3 documentation. Trying the version 3 protocol with the device, I found that it was nearly immediately functional. It seems that while the initialization procedure has changed, the position report format is identical to previous generations.

My tree[1] currently has a hacked brute-force initialization implementation, although it would probably be nice to figure out what this sequence actually means. Otherwise, it seems support for this device is a solved problem.

Feel free to give my tree a try. I'd be interested to know whether it works for you.

Cheers,

- Ben

[1] https://github.com/bgamari/linux/tree/alps

#15 lore raw
Quoted 20 lines · Ben Gamari

Ben Gamari <[email protected]> writes:

snip

Quoted 4 lines

Hopefully I'll find some more time in the next few days to figure out the last few bits (primarily how multitouch events work). I wouldn't be sad if someone finished the task for me, however.

Success! As it turns out, the process was actually not so bad. While I wasted much of the night trying to reverse the protocol, I realized that what I had come up with was nearly identical to the version 3 documentation. Trying the version 3 protocol with the device, I found that it was nearly immediately functional. It seems that while the initialization procedure has changed, the position report format is identical to previous generations.

My tree[1] currently has a hacked brute-force initialization implementation, although it would probably be nice to figure out what this sequence actually means. Otherwise, it seems support for this device is a solved problem.

Quoted 8 lines

Feel free to give my tree a try. I'd be interested to know whether it works for you.

Cheers,

- Ben

[1] https://github.com/bgamari/linux/tree/alps

Ben -

I tried your fix on a Dell Inspiron 15R N5110 (I15R). It did not work. Things I noticed:

1) Consistent with prior observations, the touchpad E7 signature for it is: 0x73 0x03 0x50, different than yours on the E6230.

2) Your alps_hw_init_v5 sequence does not work for my I15R. I noticed that the sequence enters/exits command mode a couple times. Why not enter once, do the init and then exit?

3) When in command mode, the I15R accurately sets and retrieves registers (e.g. 0x0008 returns 0x00 0x08 0x02). When not in command mode, all register reads return -1. Oddly, the check in alps_enter_command_mode is 0x73 0x01 rather than 0x88 0x07.

So I think either I'm doing something wrong or I'm dealing with YAAP (Yet Another ALPS Protocol).

My question: how did you get the protocol trace? I think you said previously that the drive does some direct register I/O. I couldn't see anything beyond PS/2 commands running under Virtual Box.

Dave

author
#16 lore raw
Quoted 8 lines · dturvene

Ben -

I tried your fix on a Dell Inspiron 15R N5110 (I15R). It did not work. Things I noticed:

1) Consistent with prior observations, the touchpad E7 signature for it
is: 0x73 0x03 0x50, different than yours on the E6230.

Alright. Good to know.

Quoted 4 lines

2) Your alps_hw_init_v5 sequence does not work for my I15R. I noticed that the sequence enters/exits command mode a couple times. Why not enter once, do the init and then exit?

Frankly, I didn't put much (honestly, any) time into figuring out the meaning behind command sequence. I grabbed a dump from the VM and implemented exactly what the Windows driver did. At that point I was under the impression I was dealing with an entirely new protocol so it didn't make much sense to put time into reasoning out the command structure. Given the v3 report format is used I should revisit this. I'll hopefully have a chance to do this this weekend. Given you seem to recognize the command structure, you could probably do this even faster than me. Take a stab at it if you feel so inclined. Pull requests accepted.

Quoted 8 lines

3) When in command mode, the I15R accurately sets and retrieves registers (e.g. 0x0008 returns 0x00 0x08 0x02). When not in command mode, all register reads return -1. Oddly, the check in alps_enter_command_mode is 0x73 0x01 rather than 0x88 0x07.

So I think either I'm doing something wrong or I'm dealing with YAAP (Yet Another ALPS Protocol).

Hopefully not.

Quoted 4 lines

My question: how did you get the protocol trace? I think you said previously that the drive does some direct register I/O. I couldn't see anything beyond PS/2 commands running under Virtual Box.

I used Seth Foreshee's method[1] under Qemu. Note that the Alps driver for the E6230 (and, given the behavior you see, likely your machine as well) checks for the presence of an entry in the ACPI DSDT (if not present, the driver falls back onto generic PS/2 behavior). Consequently, you may need to do some editing of the Qemu DSDT as pointed out earlier in this thread by James (Message-Id:
<[email protected]>) I'm not terribly familiar with ACPI, I'll defer to him to explain precisely how he determined the relevant sections.

Cheers,

- Ben

[1] http://swapspace.forshee.me/2011/11/touchpad-protocol-reverse-engineering.html

#17 lore raw
Quoted 51 lines · Ben Gamari
Quoted 8 lines · dturvene

Ben -

I tried your fix on a Dell Inspiron 15R N5110 (I15R). It did not work. Things I noticed:

1) Consistent with prior observations, the touchpad E7 signature for it
is: 0x73 0x03 0x50, different than yours on the E6230.

Alright. Good to know.

Quoted 4 lines

2) Your alps_hw_init_v5 sequence does not work for my I15R. I noticed that the sequence enters/exits command mode a couple times. Why not enter once, do the init and then exit?

Frankly, I didn't put much (honestly, any) time into figuring out the meaning behind command sequence. I grabbed a dump from the VM and implemented exactly what the Windows driver did. At that point I was under the impression I was dealing with an entirely new protocol so it didn't make much sense to put time into reasoning out the command structure. Given the v3 report format is used I should revisit this. I'll hopefully have a chance to do this this weekend. Given you seem to recognize the command structure, you could probably do this even faster than me. Take a stab at it if you feel so inclined. Pull requests accepted.

Quoted 8 lines

3) When in command mode, the I15R accurately sets and retrieves registers (e.g. 0x0008 returns 0x00 0x08 0x02). When not in command mode, all register reads return -1. Oddly, the check in alps_enter_command_mode is 0x73 0x01 rather than 0x88 0x07.

So I think either I'm doing something wrong or I'm dealing with YAAP (Yet Another ALPS Protocol).

Hopefully not.

Quoted 4 lines

My question: how did you get the protocol trace? I think you said previously that the drive does some direct register I/O. I couldn't see anything beyond PS/2 commands running under Virtual Box.

I used Seth Foreshee's method[1] under Qemu. Note that the Alps driver for the E6230 (and, given the behavior you see, likely your machine as well) checks for the presence of an entry in the ACPI DSDT (if not present, the driver falls back onto generic PS/2 behavior). Consequently, you may need to do some editing of the Qemu DSDT as pointed out earlier in this thread by James (Message-Id:
<[email protected]>) I'm not terribly familiar with ACPI, I'll defer to him to explain precisely how he determined the relevant sections.

Quoted 7 lines

Cheers,

- Ben

[1] http://swapspace.forshee.me/2011/11/touchpad-protocol-reverse-engineering.html

Hi Ben, etc. -

I just got back to looking at the Alps driver on a Dell IR15 N5110. I was using Virtualbox but switched to Qemu (1.1.1) based on your progress, patched the ps2.c and acpi-dsdt.dsl (making sure to build the hex file included in acpi.c .) I'm running vista as the guest OS, which normally loads a generic ps/2 driver. The Alps touchpad works and ps2 events are being logged. When I try to install the Alps driver, it fails because (I guess) qemu has a preconfigured notion of what hardware is running. I'm trying to figure out how to configure qemu to detect the real ALPS touchpad.

I welcome from the community and you any ideas for qemu to detect the alps touchpad.

Dave

author
#18 lore raw
Quoted 1 line · dturvene

On 08/17/2012 01:04 PM, Ben Gamari wrote:

snip

Quoted 12 lines

Hi Ben, etc. -

I just got back to looking at the Alps driver on a Dell IR15 N5110. I was using Virtualbox but switched to Qemu (1.1.1) based on your progress, patched the ps2.c and acpi-dsdt.dsl (making sure to build the hex file included in acpi.c .) I'm running vista as the guest OS, which normally loads a generic ps/2 driver. The Alps touchpad works and ps2 events are being logged. When I try to install the Alps driver, it fails because (I guess) qemu has a preconfigured notion of what hardware is running. I'm trying to figure out how to configure qemu to detect the real ALPS touchpad.

Quoted 3 lines

I welcome from the community and you any ideas for qemu to detect the alps touchpad.

If the D6430 is any indication, it seems the driver likely only checks the DSDT. Are you certain you modified this correctly to reflect your machine? You'll need to carefully compare the DSDT of your machine and that of Qemu. Given that James was the one to initially crack this one, he might have some more concrete advice.

Cheers,

- Ben

#19 lore raw
In reply to dturvene
Quoted 59 lines · dturvene
Quoted 51 lines · Ben Gamari
Quoted 8 lines · dturvene

Ben -

I tried your fix on a Dell Inspiron 15R N5110 (I15R). It did not work. Things I noticed:

1) Consistent with prior observations, the touchpad E7 signature for it
is: 0x73 0x03 0x50, different than yours on the E6230.

Alright. Good to know.

Quoted 4 lines

2) Your alps_hw_init_v5 sequence does not work for my I15R. I noticed that the sequence enters/exits command mode a couple times. Why not enter once, do the init and then exit?

Frankly, I didn't put much (honestly, any) time into figuring out the meaning behind command sequence. I grabbed a dump from the VM and implemented exactly what the Windows driver did. At that point I was under the impression I was dealing with an entirely new protocol so it didn't make much sense to put time into reasoning out the command structure. Given the v3 report format is used I should revisit this. I'll hopefully have a chance to do this this weekend. Given you seem to recognize the command structure, you could probably do this even faster than me. Take a stab at it if you feel so inclined. Pull requests accepted.

Quoted 8 lines

3) When in command mode, the I15R accurately sets and retrieves registers (e.g. 0x0008 returns 0x00 0x08 0x02). When not in command mode, all register reads return -1. Oddly, the check in alps_enter_command_mode is 0x73 0x01 rather than 0x88 0x07.

So I think either I'm doing something wrong or I'm dealing with YAAP (Yet Another ALPS Protocol).

Hopefully not.

Quoted 4 lines

My question: how did you get the protocol trace? I think you said previously that the drive does some direct register I/O. I couldn't see anything beyond PS/2 commands running under Virtual Box.

I used Seth Foreshee's method[1] under Qemu. Note that the Alps driver for the E6230 (and, given the behavior you see, likely your machine as well) checks for the presence of an entry in the ACPI DSDT (if not present, the driver falls back onto generic PS/2 behavior). Consequently, you may need to do some editing of the Qemu DSDT as pointed out earlier in this thread by James (Message-Id:
<[email protected]>) I'm not terribly familiar with ACPI, I'll defer to him to explain precisely how he determined the relevant sections.

Quoted 7 lines

Cheers,

- Ben

[1] http://swapspace.forshee.me/2011/11/touchpad-protocol-reverse-engineering.html

Quoted 7 lines

Hi Ben, etc. -

I just got back to looking at the Alps driver on a Dell IR15 N5110. I was using Virtualbox but switched to Qemu (1.1.1) based on your progress, patched the ps2.c and acpi-dsdt.dsl (making sure to build the hex file included in acpi.c .) I'm running vista as the guest OS, which normally loads a generic ps/2 driver. The Alps touchpad works and ps2 events are being logged. When I try to install the Alps driver, it fails because (I guess) qemu has a preconfigured notion of what hardware is running. I'm trying to figure out how to configure qemu to detect the real ALPS touchpad.

I welcome from the community and you any ideas for qemu to detect the alps touchpad.

Dave

I finally got this working. Briefly, it's a new protocol to init the device and the 6-byte packets coming from it are a new format. I didn't spend much time trying to understand the init sequence, just stuck the qemu packet dump into a new (V6) init function. But it works; probably needs to be tightened up a little. I don't understand the thought process behind the different protocols. It seems like the NRE to keep writing test and production drivers would be unsustainable.

I created a psmouse DLKM with a README at [1]. If there's anybody else with an N5110 who wants to try it out please post your comments.

[1]: http://www.dahetral.com/public-download

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