Bug 56681

Summary:	linux 3.8, i915, display port @ 2560x1440
Product:	Drivers	Reporter:	Tim Brown (mitnworb)
Component:	Video(DRI - Intel)	Assignee:	intel-gfx-bugs (intel-gfx-bugs)
Status:	RESOLVED CODE_FIX
Severity:	normal	CC:	chris, daniel, intel-gfx-bugs, mitnworb, tahall256
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	3.8.x+	Subsystem:
Regression:	Yes	Bisected commit-id:
Attachments:	3.7.10 Xorg.logs 3.8.7 Xorg logs Clean message log from 3.7.10 Clean message log from 3.8.7 dmesg-3.7.10 dmesg-3.8-10 dmesg-3.9.2 dmesg-3.8-10-after-xrandr

Description Tim Brown 2013-04-16 12:58:41 UTC

I'm using a monitor with DisplayPort cable. The maximal resolution of that
monitor is 2560x1440. When using a 3.7 Linux kernel everything works
like a charm.  With all the 3.8 kernels I have tried (the "official"
Arch kernels 3.8.3 and 3.8.4), I'm not longer able to use that
resolution. The maximal resolution I can get is 1920x1080 (the same
aspect ratio that the native LCD which is 1366x768).

When using the 3.8+ kernel, the machine boots but when X starts, it just
produces a black screen or a static screen that is kind of readable. I have  tried downgrading the X server, xf86-video-intel, and intel-dir without any change (I'm currently using xf86-video-intel 2.21.6-1, intel-dri 9.1.1-1, and xorg-server 1.14.0-2).

Downgrading to Linux 3.7.10-1-ARCH had solved the problem.

Comment 1 Chris Wilson 2013-04-16 13:11:10 UTC

Your Xorg.0.log with v3.8 should be a good starting point (it should have most of the information in a condensed format). Also drm.debug=6 dmesgs from booting with v3.7 and v3.8 would be useful.

Comment 2 Tim Brown 2013-04-17 16:09:41 UTC

Created attachment 99011 [details]
3.7.10 Xorg.logs

Comment 3 Tim Brown 2013-04-17 16:10:09 UTC

Created attachment 99021 [details]
3.8.7 Xorg logs

Comment 4 Tim Brown 2013-04-17 16:22:31 UTC

Created attachment 99031 [details]
Clean message log from 3.7.10

Comment 5 Tim Brown 2013-04-17 16:23:03 UTC

Created attachment 99041 [details]
Clean message log from 3.8.7

Comment 6 Daniel Vetter 2013-05-06 15:43:10 UTC

Hm, something's strange with your dmesg. drm.debug=6 is set in the kernel cmdline, but all the drm debug noise is missing. Does your distro per chance block out debug output by default? Another thing worth checking is whether the option is indeed set at runtime in /sys/module/parameters. Maybe also check whether dmesg buffer itself (see man dmesg) contains the debug stuff, but it's just filtered out in the log files.

Comment 7 Tim Brown 2013-05-06 18:29:37 UTC

Created attachment 100851 [details]
dmesg-3.7.10

Comment 8 Tim Brown 2013-05-06 18:30:07 UTC

Created attachment 100861 [details]
dmesg-3.8-10

Comment 9 Tim Brown 2013-05-06 18:30:31 UTC

Created attachment 100871 [details]
dmesg-3.9.2

Comment 10 Tim Brown 2013-05-06 18:31:24 UTC

I added three new dmesg files.  Let me know if the have what you are looking for.  I also tried version 3.9.2 with the same results.  Thanks.

Comment 11 Daniel Vetter 2013-05-06 18:48:35 UTC

Yep, logfiles look good now. But nothing jumped out which would explain what's going on here with your system, it looks like the code is still picking the same DP configuration. And nothing else seems to fail, either.

Can you please attempt to bisect where this regression has been introduced?

Comment 12 Tim Brown 2013-05-06 19:33:19 UTC

Created attachment 100891 [details]
dmesg-3.8-10-after-xrandr

This is everything after I ran xrandr --output DP3 --mode 2560x1440

I also have to run xrandr --output DP3 --mode 1024x768 to get my screen back.

Comment 13 Tim Brown 2013-08-15 15:57:38 UTC

This is working now on 3.10.5 and 3.10.6.  Thanks.