Bug: decoders referenced in kernel rc-keymaps not loaded on boot

PATCH In review Matthias Reichl 2 participants 6 messages Feb 21, 2017 – Feb 23, 2017

Subsystems (2)

Media (V4L/DVB) RC-core / lirc framework

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Matthias Reichl

author

2017-02-21 18:49 UTC #0 lore raw

There seems to be a bug in on-demand loading of IR protocol decoders.

After bootup the protocol referenced in the in-kernel rc keymap shows up as enabled (in sysfs and ir-keytable) but the protocol decoder is not loaded and thus no rc input events will be generated.

For example, RPi3 with kernel 4.10 and gpio-ir-recv configured to use the rc-hauppauge keymap in devicetree:

# lsmod | grep '^\(ir\|rc_\)'
ir_lirc_codec           5590  0
rc_hauppauge            2422  0
rc_core                24320  5 rc_hauppauge,ir_lirc_codec,lirc_dev,gpio_ir_recv

# cat /sys/class/rc/rc0/protocols
other unknown [rc-5] nec rc-6 jvc sony rc-5-sz sanyo sharp mce_kbd xmp cec [lirc]

# dmesg | grep "IR "
[    4.506728] Registered IR keymap rc-hauppauge
[    4.554651] lirc_dev: IR Remote Control driver registered, major 242
[    4.576490] IR LIRC bridge handler initialized

The same happens with other IR receivers, eg the streamzap receiver, which uses the rc-5-sz protocol / ir_rc5_decoder, on x86.

Reverting the on-demand-loading patches

[media] media: rc: remove unneeded code
commit c1500ba0b61e9abf95e0e7ecd3c4ad877f019abe

[media] media: rc: move check whether a protocol is enabled to the core commit d80ca8bd71f0b01b2b12459189927cb3299cfab9

[media] media: rc: load decoder modules on-demand
commit acc1c3c688ed8cc862ddc007eab0dcef839f4ec8

restores the previous behaviour, all decoders are enabled and IR events can be generated immediately after boot without having to manually trigger loading of a protocol decoder.

so long,

Hias

Sean Young

maintainer

2017-02-21 19:34 UTC #1 lore raw

Quoted 33 lines · Matthias Reichl

There seems to be a bug in on-demand loading of IR protocol decoders.
After bootup the protocol referenced in the in-kernel rc keymap shows up as enabled (in sysfs and ir-keytable) but the protocol decoder is not loaded and thus no rc input events will be generated.
For example, RPi3 with kernel 4.10 and gpio-ir-recv configured to use the rc-hauppauge keymap in devicetree:
# lsmod | grep '^\(ir\|rc_\)'
ir_lirc_codec           5590  0
rc_hauppauge            2422  0
rc_core                24320  5 rc_hauppauge,ir_lirc_codec,lirc_dev,gpio_ir_recv
# cat /sys/class/rc/rc0/protocols
other unknown [rc-5] nec rc-6 jvc sony rc-5-sz sanyo sharp mce_kbd xmp cec [lirc]
# dmesg | grep "IR "
[    4.506728] Registered IR keymap rc-hauppauge
[    4.554651] lirc_dev: IR Remote Control driver registered, major 242
[    4.576490] IR LIRC bridge handler initialized
The same happens with other IR receivers, eg the streamzap receiver, which uses the rc-5-sz protocol / ir_rc5_decoder, on x86.
Reverting the on-demand-loading patches
[media] media: rc: remove unneeded code
commit c1500ba0b61e9abf95e0e7ecd3c4ad877f019abe
[media] media: rc: move check whether a protocol is enabled to the core commit d80ca8bd71f0b01b2b12459189927cb3299cfab9

Quoted 6 lines

[media] media: rc: load decoder modules on-demand
commit acc1c3c688ed8cc862ddc007eab0dcef839f4ec8
restores the previous behaviour, all decoders are enabled and IR events can be generated immediately after boot without having to manually trigger loading of a protocol decoder.

Hmm this seems to be working fine for me. If you write to the protocols file, eg. "echo +nec > /sys/class/rc/rc0/protocols", is ir-nec-decoder loaded and do you get any messages in dmesg (you should).

What's your config?

Thanks,
Sean

Matthias Reichl

author

2017-02-21 22:52 UTC #2 lore raw

Quoted 41 lines · Sean Young

Quoted 33 lines · Matthias Reichl
There seems to be a bug in on-demand loading of IR protocol decoders.
After bootup the protocol referenced in the in-kernel rc keymap shows up as enabled (in sysfs and ir-keytable) but the protocol decoder is not loaded and thus no rc input events will be generated.
For example, RPi3 with kernel 4.10 and gpio-ir-recv configured to use the rc-hauppauge keymap in devicetree:
# lsmod | grep '^\(ir\|rc_\)'
ir_lirc_codec           5590  0
rc_hauppauge            2422  0
rc_core                24320  5 rc_hauppauge,ir_lirc_codec,lirc_dev,gpio_ir_recv
# cat /sys/class/rc/rc0/protocols
other unknown [rc-5] nec rc-6 jvc sony rc-5-sz sanyo sharp mce_kbd xmp cec [lirc]
# dmesg | grep "IR "
[    4.506728] Registered IR keymap rc-hauppauge
[    4.554651] lirc_dev: IR Remote Control driver registered, major 242
[    4.576490] IR LIRC bridge handler initialized
The same happens with other IR receivers, eg the streamzap receiver, which uses the rc-5-sz protocol / ir_rc5_decoder, on x86.
Reverting the on-demand-loading patches
[media] media: rc: remove unneeded code
commit c1500ba0b61e9abf95e0e7ecd3c4ad877f019abe
[media] media: rc: move check whether a protocol is enabled to the core commit d80ca8bd71f0b01b2b12459189927cb3299cfab9
Quoted 6 lines
[media] media: rc: load decoder modules on-demand
commit acc1c3c688ed8cc862ddc007eab0dcef839f4ec8
restores the previous behaviour, all decoders are enabled and IR events can be generated immediately after boot without having to manually trigger loading of a protocol decoder.

Quoted 5 lines

Hmm this seems to be working fine for me. If you write to the protocols file, eg. "echo +nec > /sys/class/rc/rc0/protocols", is ir-nec-decoder loaded and do you get any messages in dmesg (you should).
What's your config?

When I do an "echo +nec > /sys/class/rc/rc0/protocols" it triggers the load of both rc5 and nec decoder modules:

root@rpi3:~# cat /sys/class/rc/rc0/protocols
other unknown [rc-5] nec rc-6 jvc sony rc-5-sz sanyo sharp mce_kbd xmp cec [lirc]
root@rpi3:~# echo +nec > /sys/class/rc/rc0/protocols
root@rpi3:~# cat /sys/class/rc/rc0/protocols
other unknown [rc-5] [nec] rc-6 jvc sony rc-5-sz sanyo sharp mce_kbd xmp cec [lirc]
root@rpi3:~# dmesg | grep "IR "
[    3.565061] Registered IR keymap rc-hauppauge
[    3.613031] lirc_dev: IR Remote Control driver registered, major 242
[    3.641423] IR LIRC bridge handler initialized
[   41.877263] IR RC5(x/sz) protocol handler initialized
[   41.931575] IR NEC protocol handler initialized

I'm currently testing with downstream RPi kernel 4.9 on Raspbian Jessie (a Debian derivate).

Kernel config is here:
https://github.com/raspberrypi/linux/blob/rpi-4.9.y/arch/arm/configs/bcm2709_defconfig

To reproduce the issue it's important to disable the udev rule that runs ir-keytable -a as that can trigger a load of the kernel keytable via the userspace keymap/protocol.

We ran accross the issue via a bugreport from a LibreELEC user, his streamzap remote wasn't working anymore on x86 in the beta releases:
https://forum.libreelec.tv/thread-4873.html

Kernel-config for LibreELEC x86 is here:
https://github.com/LibreELEC/LibreELEC.tv/blob/libreelec-8.0/projects/Generic/linux/linux.x86_64.conf

Our analysis (I hope it's not completely off) is about this:

In the previous version (with kernel 4.4) it worked because the kernel loaded the keymap and protocol decoders. The udev rule probably failed as ir-keytable -a couldn't cope with the RC5_SZ protocol - but that went unnoticed as everything was setup fine by the kernel.

In current beta (with kernel 4.9) the kernel only loaded the keymap but didn't enable the decoder. Since ir-keytable -a again failed to setup the protocol the user was left with a non-functioning remote.

I then could reproduce this on RPi with Raspbian and LibreELEC using gpio-ir-recv. With udev/ir-keytable -a working the protocol decoder is loaded, without that it isn't.

so long,

Hias

Sean Young

maintainer

2017-02-22 23:07 UTC #3 lore raw

Quoted 66 lines · Matthias Reichl

Quoted 41 lines · Sean Young
Quoted 33 lines · Matthias Reichl
There seems to be a bug in on-demand loading of IR protocol decoders.
After bootup the protocol referenced in the in-kernel rc keymap shows up as enabled (in sysfs and ir-keytable) but the protocol decoder is not loaded and thus no rc input events will be generated.
For example, RPi3 with kernel 4.10 and gpio-ir-recv configured to use the rc-hauppauge keymap in devicetree:
# lsmod | grep '^\(ir\|rc_\)'
ir_lirc_codec           5590  0
rc_hauppauge            2422  0
rc_core                24320  5 rc_hauppauge,ir_lirc_codec,lirc_dev,gpio_ir_recv
# cat /sys/class/rc/rc0/protocols
other unknown [rc-5] nec rc-6 jvc sony rc-5-sz sanyo sharp mce_kbd xmp cec [lirc]
# dmesg | grep "IR "
[    4.506728] Registered IR keymap rc-hauppauge
[    4.554651] lirc_dev: IR Remote Control driver registered, major 242
[    4.576490] IR LIRC bridge handler initialized
The same happens with other IR receivers, eg the streamzap receiver, which uses the rc-5-sz protocol / ir_rc5_decoder, on x86.
Reverting the on-demand-loading patches
[media] media: rc: remove unneeded code
commit c1500ba0b61e9abf95e0e7ecd3c4ad877f019abe
[media] media: rc: move check whether a protocol is enabled to the core commit d80ca8bd71f0b01b2b12459189927cb3299cfab9
Quoted 6 lines
[media] media: rc: load decoder modules on-demand
commit acc1c3c688ed8cc862ddc007eab0dcef839f4ec8
restores the previous behaviour, all decoders are enabled and IR events can be generated immediately after boot without having to manually trigger loading of a protocol decoder.
Quoted 5 lines
Hmm this seems to be working fine for me. If you write to the protocols file, eg. "echo +nec > /sys/class/rc/rc0/protocols", is ir-nec-decoder loaded and do you get any messages in dmesg (you should).
What's your config?
When I do an "echo +nec > /sys/class/rc/rc0/protocols" it triggers the load of both rc5 and nec decoder modules:
root@rpi3:~# cat /sys/class/rc/rc0/protocols
other unknown [rc-5] nec rc-6 jvc sony rc-5-sz sanyo sharp mce_kbd xmp cec [lirc]
root@rpi3:~# echo +nec > /sys/class/rc/rc0/protocols
root@rpi3:~# cat /sys/class/rc/rc0/protocols
other unknown [rc-5] [nec] rc-6 jvc sony rc-5-sz sanyo sharp mce_kbd xmp cec [lirc]
root@rpi3:~# dmesg | grep "IR "
[    3.565061] Registered IR keymap rc-hauppauge
[    3.613031] lirc_dev: IR Remote Control driver registered, major 242
[    3.641423] IR LIRC bridge handler initialized
[   41.877263] IR RC5(x/sz) protocol handler initialized
[   41.931575] IR NEC protocol handler initialized
I'm currently testing with downstream RPi kernel 4.9 on Raspbian Jessie (a Debian derivate).

Quoted 6 lines

Kernel config is here:
https://github.com/raspberrypi/linux/blob/rpi-4.9.y/arch/arm/configs/bcm2709_defconfig
To reproduce the issue it's important to disable the udev rule that runs ir-keytable -a as that can trigger a load of the kernel keytable via the userspace keymap/protocol.

Ah. Yes, this is broken. In commit "9f0bf36 [media] media: rc: preparation for on-demand decoder module loading", code was added so that only the required decoder module was loaded. This added it to the sysfs protocols attribute handling, but not to the rc_register_device(), so no decoder will be loaded when a device is first registered.

As you say the udev rule papers over the problem by executing ir-keytable, so I never noticed the problem either.

I'll send a patch as a reply to this email.

Sean

Sean Young

maintainer

2017-02-22 23:11 UTC #4 lore raw

PATCH 1/1 rc: raw decoder for keymap protocol is not loaded on register

When the protocol is set via the sysfs protocols attribute, the decoder is loaded. However, when it is not when a device is first plugged in or registered.

Fixes acc1c3c ("[media] media: rc: load decoder modules on-demand")

Signed-off-by Sean Young <[email protected]>

Cc <[email protected]> # v4.5+

---
 drivers/media/rc/rc-main.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

drivers/media/rc/rc-main.c +6 -2

index 2424946..a158b32 100644
@@ -1663,6 +1663,7 @@ static int rc_setup_rx_device(struct rc_dev *dev)
 {
 	int rc;
 	struct rc_map *rc_map;
+	u64 rc_type;
 
 	if (!dev->map_name)
 		return -EINVAL;

@@ -1677,15 +1678,18 @@ static int rc_setup_rx_device(struct rc_dev *dev)
 	if (rc)
 		return rc;
 
-	if (dev->change_protocol) {
-		u64 rc_type = (1ll << rc_map->rc_type);
+	rc_type = BIT_ULL(rc_map->rc_type);
 
+	if (dev->change_protocol) {
 		rc = dev->change_protocol(dev, &rc_type);
 		if (rc < 0)
 			goto out_table;
 		dev->enabled_protocols = rc_type;
 	}
 
+	if (dev->driver_type == RC_DRIVER_IR_RAW)
+		ir_raw_load_modules(&rc_type);
+
 	set_bit(EV_KEY, dev->input_dev->evbit);
 	set_bit(EV_REP, dev->input_dev->evbit);
 	set_bit(EV_MSC, dev->input_dev->evbit);

Signature · 1 line

2.9.3

Matthias Reichl

author Tested-by on v1 1/1

2017-02-23 19:01 UTC #5 lore raw

Re: [PATCH] [media] rc: raw decoder for keymap protocol is not loaded on register

Quoted 7 lines · Sean Young

When the protocol is set via the sysfs protocols attribute, the decoder is loaded. However, when it is not when a device is first plugged in or registered.
Fixes acc1c3c ("[media] media: rc: load decoder modules on-demand")
Signed-off-by Sean Young <[email protected]>

Tested-by Matthias Reichl <[email protected]>

I've tested the backported patch below successfully on RPi3 with kernel 4.10 and decoder modules are loading fine again:

# dmesg | grep "IR "
[    3.526404] Registered IR keymap rc-hauppauge
[    3.590875] lirc_dev: IR Remote Control driver registered, major 242
[    3.600602] IR RC5(x/sz) protocol handler initialized
[    3.602111] IR LIRC bridge handler initialized

Thanks a lot for fixing this so quickly!

so long,

Hias

drivers/media/rc/rc-main.c +6 -1

index dedaf38..9a397da 100644
@@ -1441,6 +1441,7 @@ int rc_register_device(struct rc_dev *dev)
 	int attr = 0;
 	int minor;
 	int rc;
+	u64 rc_type;
 
 	if (!dev || !dev->map_name)
 		return -EINVAL;

@@ -1526,14 +1527,18 @@ int rc_register_device(struct rc_dev *dev)
 			goto out_input;
 	}
 
+	rc_type = BIT_ULL(rc_map->rc_type);
+
 	if (dev->change_protocol) {
-		u64 rc_type = (1ll << rc_map->rc_type);
 		rc = dev->change_protocol(dev, &rc_type);
 		if (rc < 0)
 			goto out_raw;
 		dev->enabled_protocols = rc_type;
 	}
 
+	if (dev->driver_type == RC_DRIVER_IR_RAW)
+		ir_raw_load_modules(&rc_type);
+
 	/* Allow the RC sysfs nodes to be accessible */
 	atomic_set(&dev->initialized, 1);