I created a report of the issue in Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199323 I'd be grateful for any tips on how to debug this further. Cheers, -olli On 4 April 2018 at 14:41, Olli Salonen <olli.salonen@xxxxxx> wrote: > Hello Peter and Max, > > I noticed that when using kernel 4.10 or newer my DVBSky S960 and > S960CI satellite USB TV tuners stopped working properly. Basically, > they will fail at one point when tuning to a channel. This typically > takes less than 100 tuning attempts. For perspective, when performing > a full channel scan on my system, the tuner tunes at least 500 times. > After the tuner fails, I need to reboot the PC (probably unloading the > driver and loading it again would do). > > 2018-04-04 10:17:36.756 [ INFO] mpegts: 12149H in 4.8E - tuning on > Montage Technology M88DS3103 : DVB-S #0 > 2018-04-04 10:17:37.159 [ ERROR] diseqc: failed to send diseqc cmd > (e=Connection timed out) > 2018-04-04 10:17:37.160 [ INFO] mpegts: 12265H in 4.8E - tuning on > Montage Technology M88DS3103 : DVB-S #0 > 2018-04-04 10:17:37.535 [ ERROR] diseqc: failed to send diseqc cmd > (e=Connection timed out) > > I did a kernel bisect between 4.9 and 4.10. It seems the commit that > breaks my tuner is the following one: > > 9d659ae14b545c4296e812c70493bfdc999b5c1c is the first bad commit > commit 9d659ae14b545c4296e812c70493bfdc999b5c1c > Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Date: Tue Aug 23 14:40:16 2016 +0200 > > locking/mutex: Add lock handoff to avoid starvation > > I couldn't easily revert that commit only. I can see that the > drivers/media/usb/dvb-usb-v2/dvbsky.c driver does use mutex_lock() and > mutex_lock_interruptible() in a few places. > > Do you guys see anything that's obviously wrong in the way the mutexes > are used in dvbsky.c or anything in that particular patch that could > cause this issue? > > Thanks and best regards, > -olli
