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 05:43:24 -0700
From:	"Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com>
To:	Frans Pop <elendil@...net.nl>,
	"Siddha, Suresh B" <suresh.b.siddha@...el.com>
CC:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	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



>-----Original Message-----
>From: Frans Pop [mailto:elendil@...net.nl]
>Sent: Friday, September 12, 2008 3:54 AM
>To: Siddha, Suresh B
>Cc: Linux Kernel Mailing List; Pallipadi, Venkatesh; Ingo
>Molnar; arjan@...ux.intel.com; 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 :-)
>

Hi,

What does the output of x86/pat_memtype_list under debugfs look like?

You may need the following if you are not already mounting debugfs.
mount -t debugfs debugfs /proc/sys/debug
cat /proc/sys/debug/x86/pat_memtype_list

Thanks,
Venki
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