Bug 507962

Summary:	eDP screen does not unblank after X screensaver activates
Product:	Gentoo Linux	Reporter:	Christopher Smith <chrylis>
Component:	[OLD] Core system	Assignee:	Gentoo Kernel Bug Wranglers and Kernel Maintainers <kernel>
Status:	RESOLVED NEEDINFO
Severity:	normal
Priority:	Normal
Version:	unspecified
Hardware:	AMD64
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---
Attachments:	Xorg log dmesg Radeon register dump; no difference between blank and unblank

Description Christopher Smith 2014-04-18 06:50:51 UTC

I recently switched to the open-source Radeon driver because of stability problems with fglrx. Immediately on using it, I found that my laptop screen would turn on but not unblank after it had gone into a power-save mode (either DPMS off or simply blank mode before turning off). Switching to another VT does not unblank the screen's contents. Suspending and resuming the entire system does unblank the screen, and framebuffer contents after reboot indicate that the screensaver's lock dialog had drawn correctly.

I first encountered this problem on Linux 3.12.4 and the 7.2.0 Radeon driver. I have the same issue after upgrading to 3.14.1 and 7.3.0.

Reproducible: Always

Steps to Reproduce:
1. Activate screensaver blanking (from command-line xset, closing lid, or timeout).
2. Attempt to deactivate screensaver.
Actual Results:  
Backlight turns on but the display stays black. Lock dialog appears to render.

Expected Results:  
Display unblanks.

I have attached dmesg and Xorg logs encompassing a failed unblank and a successful suspend-resume. I'm also attaching the output of radeontool's register dump; there is no difference between the registers when the screen is on and displaying when it is on and blanked.

I am on a Dell M6600 with the ATI FirePro M8900 (Cayman), which presents itself as an HD6970.

Comment 1 Christopher Smith 2014-04-18 06:52:22 UTC

Created attachment 375164 [details]
Xorg log

Suspend-resume cycle that successfully unblanked the screen started at 110s.

Comment 2 Christopher Smith 2014-04-18 06:52:40 UTC

Created attachment 375166 [details]
dmesg

Suspend-resume cycle that successfully unblanked the screen started at 110s.

Comment 3 Christopher Smith 2014-04-18 06:53:11 UTC

Created attachment 375168 [details]
Radeon register dump; no difference between blank and unblank

Comment 4 Mike Pagano gentoo-dev

2014-10-23 23:24:51 UTC

Is this still an issue with later kernels.