Problems with Elantech touchpad in 3.18-rc2

Dear kernel input developers,

While trying out 3.18-rc2, I noticed that the Elantech touchpad on my laptop didn't work as intended anymore. Mouse movement and tapping one finger worked, but scrolling and two finger tapping did not. X.org also didn't recognise the touchpad as a synaptics touchpad anymore.

After googling around I found that i8042.nomux=0 brought it back to normal.

My laptop is a Clevo model W650SH with a keyboard and a touchpad attached, and no touchschreen. Some output of dmesg is listed at the bottom, and the result of dmidecode is attached.

Best regards,

Roel Aaij

Some dmesg output without i8042.nomux=0 (not fully functional touchpad)

[    1.221297] i8042: PNP: PS/2 Controller [PNP0303:PS2K,PNP0f13:ELNM] at 0x60,0x64 irq 1,12
[    1.226412] serio: i8042 KBD port at 0x60,0x64 irq 1
[    1.226414] serio: i8042 AUX port at 0x60,0x64 irq 12
[    1.229415] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input6
[    5.017142] psmouse serio1: elantech: assuming hardware version 3 (with firmware version 0x450f02)
[    5.018055] psmouse serio1: elantech: elantech_send_cmd query 0x02 failed.
[    5.018057] psmouse serio1: elantech: failed to query capabilities.
[    5.930158] input: PS/2 Elantech Touchpad as /devices/platform/i8042/serio1/input/input8

Some dmesg output with i8042.nomux=0 (fully functional touchpad)

[    1.361320] i8042: PNP: PS/2 Controller [PNP0303:PS2K,PNP0f13:ELNM] at 0x60,0x64 irq 1,12
[    1.366134] i8042: Detected active multiplexing controller, rev 1.1
[    1.367757] serio: i8042 KBD port at 0x60,0x64 irq 1
[    1.367759] serio: i8042 AUX0 port at 0x60,0x64 irq 12
[    1.367764] serio: i8042 AUX1 port at 0x60,0x64 irq 12
[    1.367765] serio: i8042 AUX2 port at 0x60,0x64 irq 12
[    1.367766] serio: i8042 AUX3 port at 0x60,0x64 irq 12
[    1.371243] input: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input6
[   99.389964] psmouse serio2: elantech: assuming hardware version 3 (with firmware version 0x450f02)
[   99.489797] psmouse serio2: elantech: Synaptics capabilities query result 0x79, 0x17, 0x0c.
[   99.819119] input: ETPS/2 Elantech Touchpad as /devices/platform/i8042/serio2/input/input22

P.S. The late timestamps in the last few lines are due to a "modprobe -r psmouse && modprobe psmouse"

# dmidecode 2.12
SMBIOS 2.7 present.
34 structures occupying 1874 bytes.
Table at 0x000EB500.

Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
Vendor: American Megatrends Inc.
Version: 1.00.05
Release Date: 08/07/2013
Address: 0xF0000
Runtime Size: 64 kB
ROM Size: 4096 kB
Characteristics:
PCI is supported
BIOS is upgradeable
BIOS shadowing is allowed
Boot from CD is supported Selectable boot is supported
EDD is supported
Print screen service is supported (int 5h) 8042 keyboard services are supported (int 9h) Printer services are supported (int 17h) ACPI is supported
USB legacy is supported
BIOS boot specification is supported Targeted content distribution is supported UEFI is supported
BIOS Revision: 4.6

Handle 0x0001, DMI type 1, 27 bytes
System Information
Manufacturer: Notebook
Product Name: W65_W670SH
Version: Not Applicable
Serial Number: Not Applicable
UUID: ECF59000-47ED-0000-0000-000000000000 Wake-up Type: Power Switch
SKU Number: Not Applicable
Family: Not Applicable

Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
Manufacturer: Notebook
Product Name: W65_W670SH
Version: Not Applicable
Serial Number: Not Applicable
Asset Tag: Tag 12345
Features:
Board is a hosting board
Board is replaceable
Location In Chassis: Not Applicable
Chassis Handle: 0x0003
Type: Motherboard
Contained Object Handles: 0

Handle 0x0003, DMI type 3, 22 bytes
Chassis Information
Manufacturer: Notebook
Type: Laptop
Lock: Not Present
Version: N/A
Serial Number: None
Asset Tag: No Asset Tag
Boot-up State: Safe
Power Supply State: Safe
Thermal State: Safe
Security Status: None
OEM Information: 0x00000000
Height: Unspecified
Number Of Power Cords: 1
Contained Elements: 0
SKU Number: To be filled by O.E.M.

Handle 0x0004, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J1A1
Internal Connector Type: None
External Reference Designator: PS2Mouse
External Connector Type: PS/2
Port Type: Mouse Port

Handle 0x0005, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J1A1
Internal Connector Type: None
External Reference Designator: Keyboard
External Connector Type: PS/2
Port Type: Keyboard Port

Handle 0x0006, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J2A1 Internal Connector Type: None
External Reference Designator: TV Out External Connector Type: Mini Centronics Type-14 Port Type: Other

Handle 0x0007, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J2A2A
Internal Connector Type: None
External Reference Designator: COM A
External Connector Type: DB-9 male
Port Type: Serial Port 16550A Compatible

Handle 0x0008, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J2A2B
Internal Connector Type: None
External Reference Designator: Video
External Connector Type: DB-15 female
Port Type: Video Port

Handle 0x0009, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J3A1
Internal Connector Type: None
External Reference Designator: USB1
External Connector Type: Access Bus (USB)
Port Type: USB

Handle 0x000A, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J3A1
Internal Connector Type: None
External Reference Designator: USB2
External Connector Type: Access Bus (USB)
Port Type: USB

Handle 0x000B, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J3A1
Internal Connector Type: None
External Reference Designator: USB3
External Connector Type: Access Bus (USB)
Port Type: USB

Handle 0x000C, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J5A1
Internal Connector Type: None
External Reference Designator: LAN
External Connector Type: RJ-45
Port Type: Network Port

Handle 0x000D, DMI type 8, 9 bytes
Port Connector Information
Internal Reference Designator: J5A1
Internal Connector Type: None
External Reference Designator: USB4
External Connector Type: Access Bus (USB)
Port Type: USB

Handle 0x000E, DMI type 9, 17 bytes
System Slot Information
Designation: J6B2
Type: x16 PCI Express
Current Usage: In Use
Length: Long
ID: 0
Characteristics:
3.3 V is provided
Opening is shared
PME signal is supported
Bus Address: 0000:00:01.0

Handle 0x000F, DMI type 10, 8 bytes
On Board Device 1 Information
Type: Video
Status: Enabled
Description: To Be Filled By O.E.M.
On Board Device 2 Information
Type: Ethernet
Status: Enabled
Description: To Be Filled By O.E.M.

Handle 0x0010, DMI type 11, 5 bytes
OEM Strings
String 1: 1558
String 2: OEM String
String 3: To Be Filled By O.E.M.
String 4: To Be Filled By O.E.M.
String 5: BIOS:1.00.05

Handle 0x0011, DMI type 12, 5 bytes
System Configuration Options
Option 1: To Be Filled By O.E.M.

Handle 0x0012, DMI type 24, 5 bytes
Hardware Security
Power-On Password Status: Disabled
Keyboard Password Status: Disabled
Administrator Password Status: Disabled
Front Panel Reset Status: Disabled

Handle 0x0013, DMI type 32, 20 bytes
System Boot Information
Status: No errors detected

Handle 0x0014, DMI type 4, 42 bytes
Processor Information
Socket Designation: SOCKET 0
Type: Central Processor
Family: Core i7
Manufacturer: Intel
ID: C3 06 03 00 FF FB EB BF
Signature: Type 0, Family 6, Model 60, Stepping 3 Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported) APIC (On-chip APIC hardware supported) SEP (Fast system call)
MTRR (Memory type range registers) PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported) PAT (Page attribute table)
PSE-36 (36-bit page size extension) CLFSH (CLFLUSH instruction supported) DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (FXSAVE and FXSTOR instructions supported) SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Multi-threading)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Intel(R) Core(TM) i7-4700MQ CPU @ 2.40GHz
Voltage: 1.2 V
External Clock: 100 MHz
Max Speed: 3800 MHz
Current Speed: 2400 MHz
Status: Populated, Enabled
Upgrade: Socket rPGA988B
L1 Cache Handle: 0x0016
L2 Cache Handle: 0x0015
L3 Cache Handle: 0x0017
Serial Number: Not Specified
Asset Tag: Fill By OEM
Part Number: Fill By OEM
Core Count: 4
Core Enabled: 4
Thread Count: 8
Characteristics:
64-bit capable

Handle 0x0015, DMI type 7, 19 bytes
Cache Information
Socket Designation: CPU Internal L2
Configuration: Enabled, Not Socketed, Level 2 Operational Mode: Write Back
Location: Internal
Installed Size: 1024 kB
Maximum Size: 1024 kB
Supported SRAM Types:
Unknown
Installed SRAM Type: Unknown
Speed: Unknown
Error Correction Type: Single-bit ECC System Type: Unified
Associativity: 8-way Set-associative

Handle 0x0016, DMI type 7, 19 bytes
Cache Information
Socket Designation: CPU Internal L1
Configuration: Enabled, Not Socketed, Level 1 Operational Mode: Write Back
Location: Internal
Installed Size: 256 kB
Maximum Size: 256 kB
Supported SRAM Types:
Unknown
Installed SRAM Type: Unknown
Speed: Unknown
Error Correction Type: Single-bit ECC System Type: Other
Associativity: 8-way Set-associative

Handle 0x0017, DMI type 7, 19 bytes
Cache Information
Socket Designation: CPU Internal L3
Configuration: Enabled, Not Socketed, Level 3 Operational Mode: Write Back
Location: Internal
Installed Size: 6144 kB
Maximum Size: 6144 kB
Supported SRAM Types:
Unknown
Installed SRAM Type: Unknown
Speed: Unknown
Error Correction Type: Single-bit ECC System Type: Unified
Associativity: 12-way Set-associative

Handle 0x0018, DMI type 16, 23 bytes
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: None
Maximum Capacity: 32 GB
Error Information Handle: Not Provided
Number Of Devices: 4

Handle 0x0019, DMI type 17, 34 bytes
Memory Device

	Array Handle: 0x0018
	Error Information Handle: Not Provided
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 8192 MB
	Form Factor: SODIMM
	Set: None
	Locator: ChannelA-DIMM0
	Bank Locator: BANK 0
	Type: DDR3
	Type Detail: Synchronous
	Speed: 1600 MHz
	Manufacturer: 1315
	Serial Number: 12230000
	Asset Tag: 9876543210
	Part Number: CT102464BF160B.C16
	Rank: 2
	Configured Clock Speed: 1600 MHz

Handle 0x001A, DMI type 20, 35 bytes
Memory Device Mapped Address

	Starting Address: 0x00000000000
	Ending Address: 0x001FFFFFFFF
	Range Size: 8 GB
	Physical Device Handle: 0x0019
	Memory Array Mapped Address Handle: 0x001E
	Partition Row Position: Unknown
	Interleave Position: Unknown
	Interleaved Data Depth: Unknown

Handle 0x001B, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0018
Error Information Handle: Not Provided
Total Width: Unknown
Data Width: Unknown
Size: No Module Installed
Form Factor: DIMM
Set: None
Locator: ChannelA-DIMM1
Bank Locator: BANK 1
Type: Unknown
Type Detail: None
Speed: Unknown
Manufacturer: [Empty]
Serial Number: [Empty]
Asset Tag: 9876543210
Part Number: [Empty]
Rank: Unknown
Configured Clock Speed: Unknown

Handle 0x001C, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0018
Error Information Handle: Not Provided
Total Width: Unknown
Data Width: Unknown
Size: No Module Installed
Form Factor: DIMM
Set: None
Locator: ChannelB-DIMM0
Bank Locator: BANK 2
Type: Unknown
Type Detail: None
Speed: Unknown
Manufacturer: [Empty]
Serial Number: [Empty]
Asset Tag: 9876543210
Part Number: [Empty]
Rank: Unknown
Configured Clock Speed: Unknown

Handle 0x001D, DMI type 17, 34 bytes
Memory Device
Array Handle: 0x0018
Error Information Handle: Not Provided
Total Width: Unknown
Data Width: Unknown
Size: No Module Installed
Form Factor: DIMM
Set: None
Locator: ChannelB-DIMM1
Bank Locator: BANK 3
Type: Unknown
Type Detail: None
Speed: Unknown
Manufacturer: [Empty]
Serial Number: [Empty]
Asset Tag: 9876543210
Part Number: [Empty]
Rank: Unknown
Configured Clock Speed: Unknown

Handle 0x001E, DMI type 19, 31 bytes
Memory Array Mapped Address

	Starting Address: 0x00000000000
	Ending Address: 0x001FFFFFFFF
	Range Size: 8 GB
	Physical Array Handle: 0x0018
	Partition Width: 4

Handle 0x0022, DMI type 131, 64 bytes
OEM-specific Type

	Header and Data:
		83 40 22 00 31 00 00 00 00 00 00 00 00 00 00 00
		F8 00 49 8C 00 00 00 00 01 20 00 00 00 00 09 00
		7A 05 0D 00 00 00 00 00 C8 00 FF FF 00 00 00 00
		00 00 00 00 66 00 00 00 76 50 72 6F 00 00 00 00

Handle 0x0023, DMI type 13, 22 bytes
BIOS Language Information
Language Description Format: Long Installable Languages: 1
en|US|iso8859-1
Currently Installed Language: en|US|iso8859-1

Handle 0x0025, DMI type 127, 4 bytes
End Of Table

Hi Roel,

Argh, so quick search shows that there might be quite a few clones of W650SH floating around, and I wonder if any of W650SF/W650SJ/W670SJQ/ W650SR/W650SZ exhibit the same behavior.

We might need to revert the nomux back to the original setting, although I really do not want to do this: in my opinion it is better to have touchpad revert to basic mode on affected laptops and work on re-enabling MUX on them instead of having touchpad/keyboard completely hosed from the get-go.

Linus, any guidance here? Can we live with such regression?

Thanks.

Dmitry

No. If people are already finding machines with problems, that means that there will be a lot of them once distributions move to that kernel.

And I'd much rather maintain an old blacklist of broken machines, than start from scratch and have a whitelist for machines that want muxing.

So I guess we'll need to revert and go back to the bad old days.

That said, before we do that, maybe we can find a middle ground for the default behavior. The old behavior is to always try to mux if the hw seems to support it. The new behavior is to never try to mux by default. How about "try to mux if the controller seems to support it, but if you don't actually find any muxed devices behind the controller, go back to no-mux mode"?

Is there any way to do something like that? I don't actually know how the heck people set up those touchpads, so maybe I'm just whistling in the dark, and you can't even tell.

IOW, can we just enumerate the muxed devices, and see if they actually use anything else than just index zero? Make the default a bit more dynamic than just "all on" or "all off"?

Put another way: right now we do a lot of checking in i8042_check_aux(), but we don't do *any* checking of the individual muxed ports. Could we perhaps do some check per mux port? Do some PSMOUSE_CMD_ENABLE thing and see if you get anything back?

Am I being crazy again?

Linus

My only argument here is that failure is much less severe than with MUX
case: when in legacy mode the worst that is happening is that advanced features (multi-touch, two-finger scroilling, etc) do not work so the experience is similar to Windows box with no venrod drivers installed. Whereas when active MUX does not work but we are tying to use it your device is completely hosed.

Very often (most often) with broken MUX we do see the device, it simply does not react properly (refuses to get enabled, fails to activate in advanced mode, spews garbage into data stream, etc), so I don't think that putting entire psmouse initialization sequence with all various protocols into i8042_check_aux() is good idea.

And I have no idea whatsoever how they will behave if you try activating MUX mode, try using it, and then deactivate. I think that code path is even less travelled than active MUX one.

Dmitry

So I slept on it and I decided that we should indeed revert the patch, since it causes more grief to people with good hardware than I expected. We should not punish owners of good hardware because some vendors can't write their firmware.

Thanks.

Dmitry

You can still add "for anything manufactured in 2015+, assume it does not need MUX" and add a whitelist entry for any machine with external ps/2 ports that still needs it... I guess there would be very little of them made in 2015+.
Pavel

(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

No, that Clevo W650SH that Roel has is a Haswell and is fairly recent and has no external PS/2 ports and still wants to be in active MUX mode. So we'll have to continue with the blacklist I'm afraid.

Dmitry