[Intel-gfx] Picture quality on laptop LCD with i915GM chipset

[SD]

> From: Jin, Gordon <gordon.jin at intel.com>
> Subject: RE: [Intel-gfx] Picture quality on laptop LCD with i915GM chipset
> To: "SD" <sd.domrep at yahoo.com>, "intel-gfx at lists.freedesktop.org" <intel-gfx at lists.freedesktop.org>
> Date: Wednesday, May 19, 2010, 6:03 AM
> SD wrote on Wednesday, May 19, 2010
> 8:32 AM:
> >>> From: Clemens Eisserer <linuxhippy at
> gmail.com>
> >>> Subject: Re: [Intel-gfx] Picture quality on
> laptop LCD with i915GM
> >>> chipset. To: "intel-gfx" <intel-gfx at
> lists.freedesktop.org>
> >>> Date: Saturday, May 15, 2010, 12:56 PM
> >>> Hi,
> >>> 
> >>> Why don't you record a video or take a
> screenshot to make
> >>> at least
> >>> clear to us whats going on?
> >>> 
> >>> - Clemens
> >> 
> >> I do not blame anyone, I know you all want to
> help.
> >> I tried to take a picture and take a video, but
> unfortunately 30
> >> frame per second can't catch it. Everything looks
> nice. 
> >> I will try to explain again. In compare with
> kernel up to 2.6.27
> >> (because I used Ubuntu, Mandriva), 2.6.33
> looks:more brighter, may
> >> be more contrast, especially white, it is
> definitely more brighter
> >> although I stated xgamma 0.75. But biggest problem
> is that colors of
> >> the picture are not solid, stable - they are
> somehow blinking or
> >> flickering. Sometime I think may be back lights of
> LCD panel works
> >> different. And after hour or two eyes start notice
> it, it is looks
> >> like colors is not constant, they always changes,
> little bit but
> >> they are "playing". It is very noticeable if I log
> into different
> >> TTY (not graphical) and just start "mc" - it
> present for eyes.      
> >> It is impossible to record, sorry.
> >> 
> >> Thanks for help.
> >> 
> >>> 
> >>>> I have tried OpenSuse 11.2, which is with
> newer kernel
> >>> and it shows the same bad like Fedora 12. So I
> decided to
> >>> shift on fedora, but unfortunately although
> Fedora 13 shows
> >>> screen better - it is still not usable
> (actually screen
> >>> picture on Fedora 12 was really awful). I have
> tried to
> >>> compare video output on OpenSuse 11.1 and
> Fedora 13, all of
> >>> the has the same, except of "xdpyinfo": on
> suse it tells
> >>> about 3 visuals ( number of visuals: 
>   3), but on Fedora
> >>> 13 - 32 visuals. Fedora 12 got 72.
> >>>> 
> >>>> Problems is not with fonts at all, problem
> with whole
> >>> screen. Font, because it very contrast, is
> more noticeable.
> >>> Also, of course I use freetype for the full
> hinting.
> >>>> Does it happened to all intel chipset, or
> to only
> >>> i915GM, because I of course going to change my
> laptop, and
> >>> it looks like I am not going to by a one with
> intel video.
> >>>> 
> >>>> Thanks.
> > 
> > 
> > 
> > Dear All.
> > 
> > At last, I found the problem - it is new kernel 33 and
> 34, I took
> > them from Fedora. 
> > I put them to my OpenSuse 11.1 (27 kernel) and boot it
> up.
> > Picture of the screen became unusable. And it is not
> Xorg with its
> > drivers, because except of the kernel everything from
> OpenSuse 11.1 -
> > it is kernel.  
> > I do not know how it works with other GPU (intel or
> nvidia), but mine
> > i915GM shows awful screen. 
> > I know what is wrong with picture - colors of the
> pixels. They are
> > not static, they change. Little bit, but change. It
> became more
> > noticeable when I just reboot. For example white - it
> is white, but
> > it changes around white, and as color is brighter it
> is more
> > annoying. 
> 
> Flickering? Does booting kernel with i915.powersave=0
> work?
> 
> > May be I am wrong about all of it, I for sure - I am
> not
> > going to use 33 and 34 kernel with i915GM. 
>   
> 


> Just checked on Fedora Rawhide 34 kernel. Booted with i915.powersave=0 -
> there is no difference.
> I would say that pixel changes brightness. For example, I found a 1 pixel line on
> fxce panel - white line surrounding by gray aria. And it is possible to notice that
> pixels on gray line next to white is not constantly gray, they are flickering or
> changing brightness.


I am happy to say that I found source of my problems.
DRI2 module.

As long as I start Xorg with "Disable DRI2" in module section I have normal picture and I have normal smooth rotatin of the gears in "glxgears" test.
Output of the "glxgears" without dri2 module:
565 frames in 5.0 seconds = 112.932 FPS
559 frames in 5.0 seconds = 111.726 FPS
558 frames in 5.0 seconds = 111.590 FPS
554 frames in 5.0 seconds = 110.797 FPS
569 frames in 5.0 seconds = 113.742 FPS
XIO:  fatal IO error 11 (Resource temporarily unavailable) on X server ":0.0"
      after 6301 requests (36 known processed) with 0 events remaining.

Output of TOP:
1676 vas       20   0 15784 4868 1760 R 52.6  0.3   0:03.75 glxgears
1032 root      20   0 53664  12m 7124 S 39.9  0.8   0:50.63 X

Of course there is no H/W acceleration, but no more eyes problems also.

I am happy, I can use fedora.