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

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Date:	Fri, 12 Sep 2008 12:54:01 +0200
From:	Frans Pop <elendil@...net.nl>
To:	Suresh Siddha <suresh.b.siddha@...el.com>
Cc:	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

Bug-Entry  : http://bugzilla.kernel.org/show_bug.cgi?id=10843

On Wednesday 25 June 2008, Suresh Siddha wrote:
> On Mon, Jun 23, 2008 at 05:38:59AM -0700, Frans Pop wrote:
> > On Sunday 15 June 2008, Siddha, Suresh B wrote:
> > > Frans, With or without pat, in the recent kernels (like
> > > 2.6.26-rc4/rc5 etc), ioremap() uses  UC- and PCI mmap of
> > > /sys/devices/pci.../resource (used by X) uses UC-
> > >
> > > And fb_mmap() also uses UC-.
> > >
> > > It's interesting that you don't see this artifact with "nopat".
> > > Essentially with or with out pat enabled, we use the same memory
> > > attributes. So depending on the MTRR setup (set by X server),
> > > effective memory attribute across different mappings should be same
> > > (which is UC- or WC with mtrr).
> >
> > Any progress on this issue? It's still there with -rc7, but I doubt
> > that comes as a surprise.
> >
> > Has anyone tried to reproduce this? I would think that should be
> > trivial.
> >
> > Just as a summary:
> > - Intel 82945G/GZ graphics [8086:2772] (ICH7 based system)
> > - FB_VESA=y, FRAMEBUFFER_CONSOLE=y
> > - boot with vga=791
> > - Log in to X and KDE; I do need to really log in there are no
> >   artifacts if I exit X from the kdm login dialog
> > - artifacts show on logout
> >
>
> FJP, We will try to reproduce this and getback.

Hello all,

I'd like to bring this issue to your attention once again as it is still 
present in 2.6.27-rc6.

Note also that I can trivially reproduce exactly the same behavior on 
three rather different systems. The artifacts even look similar and in 
all cases they disappear with 'nopat'.

The systems are:
Toshiba Satellite A40 laptop:
- Intel 82852/855GM Integrated Graphics Device [8086:3582]
- ICH4 based
- Mobile Intel Pentium 4 processor, i386 kernel
Intel desktop system:
- Intel 82945G/GZ Integrated Graphics Controller [8086:2772]
- ICH7 based
- Pentium D processor, x86_64 kernel
HP Compaq 2510p laptop:
- Intel Mobile GM965/GL960 Integrated Graphics Controller [8086:2a02]
- ICH8 based
- Core2 Duo processor, x86_64 kernel

Have you had any luck reproducing it?

> Your earlier responses did not give many clues.

Well, unfortunately I can only provide the info you ask for :-)

Cheers,
FJP
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