DVI output > monitor blinking at max res. in X session (VGA - OK, text mode OK)

Alex Deucher alexdeucher at gmail.com
Mon Feb 4 09:13:22 PST 2013

On Sun, Feb 3, 2013 at 7:54 AM, Eduard Tibet <eduard.tibet at gmail.com> wrote:
> Hello!
> I've already post this message to other several X-related forums some
> time ago, but unfortunately I didn't get some information from there.
> Seems that other people didn't faced such problems. Searching this
> list for such problem gives some results but don't seem to be the same
> as mine.
> Initial state:
> I have 1 graphic card (based on ATI Radeon 9200) and 2 monitors (both
> EIZO) with Debian 6.0 powered PC (default kernel
> Monitors have different resolutions: S1961 (1280x1024) and L985EX
> (1600x1200). I use only single monitor each time (the other one even
> doesn't connected to signal output). Both are works OK in console
> (text) modes at all outputs (so technically they are seems to be OK).
> S1961 works OK in all modes at all outputs in X session (DVI, VGA).
> But L985EX has very strange problem: it works OK in all modes at VGA
> output, but begins to blink when using DVI output. It seems like
> monitor probing procedure takes place (i.e.: blank screen 1-2 sec. >
> restoring image 2-3 sec. > blank screen again 1-2 sec. > restoring
> image 2-3 sec.). Other interesting thing that the frequency of such
> behaviour is mostly depends on resolution. At default (max res.)
> 1600x1200 there are no possible to do anything in X session (blanking
> and stable image are approx. 2 sec. each). If I change the resolution
> to 1280x1024 X session begin more stable (blanking for 1 sec with
> 20-30 sec. interval of stable image). If I change the resolution
> futher to 1024x768 X session begin most stable at DVI output. I don't
> face any blinking at all.

Sounds like display bandwidth issues.  You might try setting the
display priority to high:
As per your attempt 4 below.  As for the error you are getting, your
kernel may be too old to support that parameter.  A newer kernel may
work better in general.


> My experiments to solve the issue:
> Try 1. First I tried to use other hdd with other non X-based OS and it
> seems to be OK at 1600x1200 at DVI so it seems not to be a real
> hardware problem.
> Try 2. Then I tried to upgrade X.org to most recent version from
> debian backports repo (first - was, second - upgraded): xserver-xorg
> (7.5.8 > 7.6.8), xserver-xorg-core ( >
> xserver-xorg-video-radeon ( > Sorry for the
> packages name - they are debian specific, because I don't know how it
> called in X repo. But nothing happened.
> Try 3. I tried to play with xrandr modes, but no success.
> Try 4. I tried to put radeon.disp_priority=2 at kernel boot (as
> mentioned at [1], [2], [3]) but got an error message: "[5.433004]
> radeon: Unknown parameter `disp_priority'" (initial call string:
> [0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-2.6.32-5-686
> root=UUID=4ddfc6de-7006-47ae-b142-7fdf1228beae ro quiet
> radeon.disp_priority=2 )
> Now I don't know where to digg to solve the issue.
> I know that I need to provide the X.org.log and dmesg.out, but I don't
> know, if I allowed to send it directly to the list.
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=26552
> [2] https://bugs.freedesktop.org/show_bug.cgi?id=33657
> [3] https://bugs.freedesktop.org/show_bug.cgi?id=48772
> --
> regards, Eduard
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