Bug 21388 - Dual monitor setup results in blank screen on CRTC1
Summary: Dual monitor setup results in blank screen on CRTC1
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/radeonhd (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium major
Assignee: Luc Verhaegen
QA Contact: Xorg Project Team
Depends on:
Reported: 2009-04-24 09:30 UTC by Michal Svoboda
Modified: 2011-11-07 15:29 UTC (History)
0 users

See Also:
i915 platform:
i915 features:

xorg config (2.47 KB, text/plain)
2009-04-24 09:30 UTC, Michal Svoboda
no flags Details
xorg log (83.58 KB, text/plain)
2009-04-24 09:30 UTC, Michal Svoboda
no flags Details
xrandr --verbose (23.93 KB, text/plain)
2009-04-24 09:31 UTC, Michal Svoboda
no flags Details
stripes on the screen (420.39 KB, image/jpeg)
2009-06-09 06:06 UTC, Michal Svoboda
no flags Details

Description Michal Svoboda 2009-04-24 09:30:25 UTC
Created attachment 25111 [details]
xorg config

I have a dual monitor setup (see attached files); the problem is that the secondary monitor (connected to dvi2) stays black. Note that these are CRT monitors. It switches to correct mode, thus is not out of range, I can verify that via the OSD menu. I can even switch it to different modes using xrandr, but it stays black. It is not a hardware issue, dual monitors work okay in the other operating system. The theory is that CRTC1 is not properly initialized or operated. This is backed up by the fact that when the first (ie. working) monitor is plugged out before starting X, the other monitor (ie. blank) is working, and when the former first monitor is plugged back and activated via xrandr, it stays black.

I experienced a brief moment a working setup, which went as follows: the X server was first configured to run with the radeon driver, then it was shut down, then the radeonhd driver was configured. This setup resulted in both monitors working. After shutting down X again, all was back to previous state, as described above.
Comment 1 Michal Svoboda 2009-04-24 09:30:47 UTC
Created attachment 25112 [details]
xorg log
Comment 2 Michal Svoboda 2009-04-24 09:31:05 UTC
Created attachment 25113 [details]
xrandr --verbose
Comment 3 Michal Svoboda 2009-05-31 23:32:09 UTC
Perhaps another useful information would be that a workaround can be performed to achieve a working setup. Boot the computer to windows xp (yes) then restart to linux and wonders - two monitors show two images. However, this does not work 100% of the time and also again everything is lost if one quits X and attempts to restart. The randomy nature might perhaps point to a race condition?
Comment 4 Michal Svoboda 2009-06-09 06:05:54 UTC
sometimes the screen is not completely black, but shows stripes (see attachment)
Comment 5 Michal Svoboda 2009-06-09 06:06:32 UTC
Created attachment 26582 [details]
stripes on the screen
Comment 6 Jeremy Huddleston Sequoia 2011-10-16 15:57:09 UTC
Does this issue occur with the preferred ati driver (xf86-vide-ati)?  If so, please move this to the Driver/Radeon component.  

Development of radeonhd has pretty much halted and development focus is on the ati driver.  Please see http://www.x.org/wiki/radeonhd

If the issue does not exist in the ati driver (or if there is no response to this message), this bug will be closed as WONTFIX unless someone contributes a patch.
Comment 7 Jeremy Huddleston Sequoia 2011-11-07 15:29:48 UTC
Closing due to lack of response.  Please reopen and move to the Driver/Radeon 
component if this issue persists with xf86-video-ati

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