On Jul 18, 2011, at 6:29 PM, Chris W <lkml@xxxxxxxxxxxxxxx> wrote: > On 19/07/11 02:46, Jarod Wilson wrote: >> The interface 0 urb callback was being wired up before the rc_dev device >> was allocated, meaning the callback could be called with a null rc_dev, >> leading to an oops. This likely only ever happens on the older 0xffdc >> SoundGraph devices, which continually trigger interrupts even when they >> have no valid keydata, and the window in which it could happen is small, >> but its actually happening regularly for at least one user, and its an >> obvious fix. Compile and sanity-tested with one of my own imon devices. > > As the "at least one user" I can confirm that the patch has indeed > corrected the problem on my 2.6.38-gentoo-r6, 2.6.39.3 vanilla, and > 3.0.0-rc7 kernels. > > This is what loading the module with the "debug=1" option outputs: > > input: iMON Panel, Knob and Mouse(15c2:ffdc) as > /devices/pci0000:00/0000:00:10.2/usb4/4-2/4-2:1.0/input/input7 > imon 4-2:1.0: Unknown 0xffdc device, defaulting to VFD and iMON IR (id 0x00) Ugh, damn, that change broke the ffdc device auto-detection... Better than a crash, but lemme see if I can alter things slightly so we can have our cake and eat it too... > Registered IR keymap rc-imon-pad > input: iMON Remote (15c2:ffdc) as > /devices/pci0000:00/0000:00:10.2/usb4/4-2/4-2:1.0/rc/rc2/input8 > rc2: iMON Remote (15c2:ffdc) as > /devices/pci0000:00/0000:00:10.2/usb4/4-2/4-2:1.0/rc/rc2 > imon 4-2:1.0: iMON device (15c2:ffdc, intf0) on usb<4:3> initialized > usbcore: registered new interface driver imon > intf0 decoded packet: 00 00 00 00 00 00 24 01 > intf0 decoded packet: 00 00 00 00 00 00 24 01 > intf0 decoded packet: 00 00 00 00 00 00 24 01 > intf0 decoded packet: 00 00 00 00 00 00 24 01 > ... > > The decoded packet lines are fast and furious with no deliberate IR > input (the VFD is in use), which might explain how this device managed > to break the code in the small window available. Yep. I hate hate hate hate the ffdc imon hardware, for this and multiple other reasons (including the nasty hack used for ffdc device type auto-detection)... My ffdc devices do similar constant spewing, but never triggered the oops, so maybe yours is even worse, or your system is faster, or a kernel config change made a difference here... > Thank you Jarod and Andy for taking the time to track this problem down > to give it a drubbing. Thanks for the testing and patience, hopefully just one more patch to test out before we can say case closed here... --jarod -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
