Bug 91365

Summary:	VT switching breaks display on Broadwell
Product:	DRI	Reporter:	Lyude Paul <lyude>
Component:	DRM/Intel	Assignee:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Status:	CLOSED FIXED	QA Contact:	Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity:	major
Priority:	medium	CC:	intel-gfx-bugs
Version:	unspecified
Hardware:	Other
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Lyude Paul 2015-07-16 22:23:38 UTC

Hi. So, this is a pretty bad bug that I've been able to reproduce with multiple machines. The display goes bonkers when switching to a virtual terminal from Xorg. The display starts scrolling up and down like an old film projector with tons of visible corruption, and if left long enough eventually stops so half the screen is at the top and the rest of the screen is at the bottom. The only way to get it back to normal is to do something that starts up the 3D acceleration (such as opening the activities overlay in GNOME). Unfortunately, doing this so many times eventually puts the display in a state where recovery is impossible without rebooting. I've been able to reproduce this on:

- The ThinkPad T450s
- The ThinkPad X1 Carbon (latest revision)
- Chromebook Pixel

All of these systems are running Fedora 22, updated to the latest stable revision of the driver. I've tried building a mainline kernel, but the problem remains present. The version of the xorg driver is 2.99.197.

Comment 1 Chris Wilson 2015-07-16 22:44:33 UTC

IPS needs disabling when changing modes close to pll limits. Fixed upstream.

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