[Intel-gfx] Picture on i915GM laptop LCD is usable only with "DRI" "off" in xorg.conf Fedora 14

[Chris Wilson]

On Wed, 24 Nov 2010 06:05:07 -0800 (PST), SD <sd.domrep at yahoo.com> wrote:
> Dear All.
> 
> Within last few days I have been testing my laptop i915GM LCD screen picture with option "DRI" "off" in xorg.conf device section. It happened because I can't physically look at my screen more then half an hour with DRI enabled. I do not know how to explain what is wrong with LCD picture, but my eyes like burn inside, after some time screen picture starts to hurt my eyes.
> It was before already and then I solved it to disable DRI. Now with Fedora 14.
> I know, I do not blame anyone, because I start from Fedora 13, then Fedora rawhide, then Fedora 14 and always the same problem - unusable screen picture with my i915.

Most likely a vrefresh issue. Turn your head to one side, do you see any
screen flicker in your peripheral vision? If you can, using that screen
for any length of time will lead to eye strain.

For us to be able to help you, we need a lot more details about your
machine, in particular Xorg.0.log, xrandr, dmesg would be a good start.

> Disabling DRI solve it up to 80%, because it anyway stays worse then picture on Suse 11.1 (just perfect).
> 
> Another problem (and it is really problem). I know and I some of you many times told, that "glxgears" is not a test tool and I can't measure with it anything, BUT with DRI "off" option it gives me:
> 718 frames in 5.0 seconds = 143.432 FPS
> 
> With DRI enabled I got only:
> 98 frames in 5.1 seconds = 19.359 FPS (still mouse)

This is hugely important and tells you that your system configuration is
broken. Most likely you do not have permission to access the graphics
device directly (as required for hardware DRI). Unless of course, it works
correctly with a moving mouse, then you are just suffering from missing
interrupts like the rest of us.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre