I am on a Thinkpad T450, if I connect a single external monitor, either via miniDP or VGA, everything works fine. If I connect both monitors, all output disappears and the only way to restore is to go back to a text console and restart the display manager. In dmesg, I get a lot of these messages: [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)! I found other bugs that report the same error message, but they seem to be triggered by different conditions. The two monitor used to work on a previous kernel (I'm not sure what version, probably before 4.2). Additional information follows: $ uname -a Linux davide 4.4.0-040400rc3-generic #201511300321 SMP Mon Nov 30 03:23:36 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux $ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation Broadwell-U Integrated Graphics (rev 09) $ lsmod | grep i915 i915 1204224 9 i2c_algo_bit 16384 1 i915 drm_kms_helper 135168 1 i915 drm 360448 10 i915,drm_kms_helper video 40960 2 i915,thinkpad_acpi
(In reply to dbb from comment #0) > In dmesg, I get a lot of these messages: > > [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied > (SDE)! > > I found other bugs that report the same error message, but they seem to be > triggered by different conditions. I don't think this has anything to do with the bug (it's another issue, already fixed). Otherwise this is a bit thin on information; please add drm.debug=14 module parameter, and attach dmesg from boot to the problem, running latest kernels.
(In reply to Jani Nikula from comment #1) > (In reply to dbb from comment #0) > > In dmesg, I get a lot of these messages: > > > > [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied > > (SDE)! > > > > I found other bugs that report the same error message, but they seem to be > > triggered by different conditions. > > I don't think this has anything to do with the bug (it's another issue, > already fixed). > > Otherwise this is a bit thin on information; please add drm.debug=14 module > parameter, and attach dmesg from boot to the problem, running latest kernels. Thanks for the fast reply! I will do a run with the debug information as soon as I can and I'll post the dmesg output. About that error message, from what kernel version should it be fixed? I am running the lastest RC I found prebuilt for ubuntu, unfortunately I don't have too much time to build newer kernels. Thanks -
Created attachment 120272 [details] dmesg log with debug messages
Here is the log you requested. I enabled the kernel module parameter and I rebooted. Then I tried to log to KDE in without any monitors attached and I got a blank screen. Then I attached both external monitors, tried to log in again, and tried to change the monitor setup with xrandr, I never got anything to work. Then I removed the kernel module parameter, I rebooted and I had again trouble to get any output. I finally managed to start up kde with the miniDP external monitor attached. Let me know what other information might be useful.
I'm not sure if this symptom is related or if it's really another issue: When I have one external monitor attached via the miniDP port and I disconnect it, I get a black screen on the laptop and the only way to get it back is to go to a text console and restart X. I see the following in dmesg: [29129.390410] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)! [...] [29129.391716] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)! [29148.600973] kscreen_backend[1653]: segfault at 10 ip 00007eff025b68c0 sp 00007ffc47822df8 error 4 in KSC_XRandR.so[7eff025a3000+20000] [29149.332438] kactivitymanage[1630]: segfault at 18 ip 00007fa820132ee0 sp 00007ffc205b63a8 error 4 in libqxcb.so[7fa820104000+b5000] [29149.332859] kiod5[2181]: segfault at 18 ip 00007f58f0fcbee0 sp 00007ffee5450258 error 4 in libqxcb.so[7f58f0f9d000+b5000] [29149.402729] systemsettings5[19223]: segfault at 8 ip 00007fda31cf90e0 sp 00007fffac0143f8 error 4 in libQt5Gui.so.5.4.2[7fda31beb000+51b000] [29150.469080] kwin_x11[19305]: segfault at 18 ip 00007fc1d4e29e38 sp 00007ffe9043b720 error 4 in libqxcb.so[7fc1d4de0000+b5000] [29150.533715] krunner[19303]: segfault at 18 ip 00007ffba6bede38 sp 00007ffdf5735920 error 4 in libqxcb.so[7ffba6ba4000+b5000] [29150.534234] plasmashell[19301]: segfault at 18 ip 00007faa6eb0fe38 sp 00007ffed0685ed0 error 4 in libqxcb.so[7faa6eac6000+b5000] [29151.440292] klauncher[19322]: segfault at 18 ip 00007faab946be38 sp 00007ffe45ef0cc0 error 4 in libqxcb.so[7faab9422000+b5000] [29153.755640] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)! [...] [29153.789441] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)! [29153.789464] [drm:intel_dp_link_training_clock_recovery [i915]] *ERROR* failed to enable link training [29153.789988] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)! [...] interrupt lied (SDE)! [29153.792093] [drm:intel_dp_link_training_channel_equalization [i915]] *ERROR* failed to start channel equalization
Created attachment 120519 [details] New dmesg with linux-4.4.0-040400rc5-generic and xserver-xorg-video-intel-2:2.99.917+git20151019-1~exp1ubuntu1 The problem is still there.
Created attachment 120535 [details] Reproduced with latest nightly build BTW, the "[drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!" messages are still there.
The logs with drm.debug=14 module parameter indicate DP MST. Please try v4.6-rc5 or current drm-intel-nightly branch of http://cgit.freedesktop.org/drm-intel. There's been plenty of DP MST fixes lately.
Timeout. Marking this resolved+fixed after being almost a year in NEEDINFO and wihtout response. Please reopen if this is still valid and should not be closed.
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.