Bug 96469

Summary:	[BDW]: linux 4.6.2: mode switch is not reliable, gnome-shell sometimes hangs on mode switch
Product:	DRI	Reporter:	Vasily Khoruzhick <anarsoul>
Component:	DRM/Intel	Assignee:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Status:	CLOSED WORKSFORME	QA Contact:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity:	normal
Priority:	medium	CC:	intel-gfx-bugs
Version:	unspecified
Hardware:	x86-64 (AMD64)
OS:	All
Whiteboard:
i915 platform:	BDW	i915 features:	display/DP MST

Description Vasily Khoruzhick 2016-06-10 00:32:10 UTC

After upgrade to linux-4.6.2 modeswitch using xrandr is very unreliable. Gnome-shell can hang right after using xrandr. Nothing suspicious in journal, it hangs after:

Jun 09 17:19:32 vasilykh-thinkpad-x1 /usr/lib/gdm/gdm-x-session[563]: (II) intel(0): resizing framebuffer to 4480x1440
Jun 09 17:19:32 vasilykh-thinkpad-x1 /usr/lib/gdm/gdm-x-session[563]: (II) intel(0): switch to mode 2560x1440@60.0 on DP2-2 using pipe 0, position (1920, 0), rotation normal, reflection none
Jun 09 17:19:32 vasilykh-thinkpad-x1 kernel: [drm] Reducing the compressed framebuffer size. This may lead to less power savings than a non-reduced-size. Try to increase stolen memory size if available in BIOS

Hardware is Thinkpad X1 Carbon 3rd gen, Broadwell graphics. External monitor is connected using OneLink dock.

Comment 1 Jani Nikula 2016-06-10 07:35:23 UTC

Please add drm.debug=14 module parameter, and attach dmesg all the way from boot to reproducing the issue. /var/log/Xorg.0.log might be useful too.

I presume the problem does not appear with the laptop panel alone, is that right?

The dock has DP MST, which is still flaky in Linux in general. It's getting better, and fixes are flowing in. I just got a OneLink Pro dock myself yesterday for my Broadwell based Yoga 12 but haven't had the time to play with it.

Comment 2 Ricardo 2017-02-21 16:35:04 UTC

Vasily is this problem still occurring with newer kernel? further information like log will help like Jani suggest.

Comment 3 Ricardo 2017-03-03 18:56:30 UTC

There have been no activity, please review past comments to provide more complete information on the bug. lack to provide will result in closing the bug. collaboration is needed in order to work on a resolution. Once logs have been provided please change status of the bug to REOPEN.

Comment 4 Jari Tahvanainen 2017-04-19 14:34:36 UTC

Timeout - marking resolved+worksforme.

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