FS#39821 - [linux] 3.14.0-4-ARCH Secondary monitor blank and flickering with Radeon FOSS driver

Attached to Project: Arch Linux
Opened by Joe (n3hima) - Friday, 11 April 2014, 15:27 GMT
Last edited by Tobias Powalowski (tpowa) - Tuesday, 17 June 2014, 10:57 GMT
Task Type Bug Report
Category Kernel
Status Closed
Assigned To Tobias Powalowski (tpowa)
Thomas Bächler (brain0)
Architecture x86_64
Severity Medium
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

Description:
Secondary monitor (VGA) flickers white/black when X is started and various colours/black on a TTY console. The issue is fixed after downgrading to 3.13.8-1-ARCH kernel and rebooting.

Additional info:
Bug appears when using kernel 3.14.0-4-ARCH, but not 3.13.8-1-ARCH. lspci reports graphics card as Radeon HD 6670/7670. (I think it's 6670 but I can't remember.)

I'm not sure what log files to include; startx produces the same output independent of the kernel. Here is a video of the problem: https://peano.losingthegame.net/joe/brokenGFX.mp4.

When using a compositor (compton), xmonad hangs on launch, but when compton is killed, the primary display functions normally. This may be incidental.

Steps to reproduce:
Using a Radeon HD 6670/7670 card and a secondary monitor, upgrade to the 3.14.0-4-ARCH kernel and boot. Observe the secondary monitor flickering.
This task depends upon

Closed by  Tobias Powalowski (tpowa)
Tuesday, 17 June 2014, 10:57 GMT
Reason for closing:  Upstream
Comment by Joe (n3hima) - Friday, 11 April 2014, 15:28 GMT
This may be related to  FS#39795  but I'm not sure.
Comment by Thomas Bächler (brain0) - Friday, 11 April 2014, 15:38 GMT
There is nothing in the stable queue related to radeon. 3.14-4 does not change anything in the configuration related to framebuffer or DRM drivers.

Make sure to open a bug report with the radeon guys at the kernel.org bugzilla.

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