linux-kernel - Re: [Bug 10843] Display artifacts on XOrg logout with PAT kernel and VESA framebuffer

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Date:	Mon, 16 Jun 2008 01:02:10 +0200
From:	Frans Pop <elendil@...net.nl>
To:	"Siddha, Suresh B" <suresh.b.siddha@...el.com>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com>,
	Ingo Molnar <mingo@...e.hu>,
	"arjan@...ux.intel.com" <arjan@...ux.intel.com>,
	"jbarnes@...tuousgeek.org" <jbarnes@...tuousgeek.org>
Subject: Re: [Bug 10843] Display artifacts on XOrg logout with PAT kernel and VESA framebuffer

On Sunday 15 June 2008, Siddha, Suresh B wrote:
> > Bug-Entry     : http://bugzilla.kernel.org/show_bug.cgi?id=10843
> > Subject       : Display artifacts on XOrg logout with PAT kernel
> > and VESA framebuffer
> > Submitter     : Frans Pop <elendil@...net.nl>
> > Date          : 2008-05-31 14:04 (15 days old)
> > References    : http://lkml.org/lkml/2008/6/7/206
>
> Can you also check, if there is any impact with kernel boot param for
> vesafb "mtrr:3"?

Hello Suresh. Thanks for responding.

I've done 4 successive boots with the boot parameters as shown below.
Each boot was basically: set correct parameters in grub -> login to KDE
                         -> reboot and check for artifacts.

1) (none)                      --> clean
2) vga=791                     --> artifacts
3) vga=791 nopat               --> clean
4) vga=791 video=vesafb:mtrr:3 --> artifacts

So the mtrr option did not help (if I passed it correctly; the double ":"
is somewhat non-intuitive). The kernel log also does not show any
difference I can see in the last boot, but I don't know if the mtrr option
is supposed to show up in any way.

>From the kernel log for each boot:
1) x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
   Console: colour VGA+ 80x25
   console [tty0] enabled

2) x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
   Console: colour dummy device 80x25
   console [tty0] enabled
   vesafb: framebuffer at 0x80000000, mapped to 0xffffc20000900000, using 3072k, total 7872k
   vesafb: mode is 1024x768x16, linelength=2048, pages=4
   vesafb: scrolling: redraw
   vesafb: Truecolor: size=0:5:6:5, shift=0:11:5:0
   Console: switching to colour frame buffer device 128x48
   fb0: VESA VGA frame buffer device

3) PAT support disabled
   Console: colour dummy device 80x25
   console [tty0] enabled
   vesafb: framebuffer at 0x80000000, mapped to 0xffffc20000900000, using 3072k, total 7872k
   vesafb: mode is 1024x768x16, linelength=2048, pages=4
   vesafb: scrolling: redraw
   vesafb: Truecolor: size=0:5:6:5, shift=0:11:5:0
   Console: switching to colour frame buffer device 128x48
   fb0: VESA VGA frame buffer device

4) x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
   Console: colour dummy device 80x25
   console [tty0] enabled
   vesafb: framebuffer at 0x80000000, mapped to 0xffffc20000900000, using 3072k, total 7872k
   vesafb: mode is 1024x768x16, linelength=2048, pages=4
   vesafb: scrolling: redraw
   vesafb: Truecolor: size=0:5:6:5, shift=0:11:5:0
   Console: switching to colour frame buffer device 128x48
   fb0: VESA VGA frame buffer device

Hope that helps. If you need any additional information, please ask.

Cheers,
FJP
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