Problem with the xorg ati driver and kexec/kdump

[Dave Airlie]

I'm not sure about kexec/kdump exactly, but you are leaving the mach64
setup and execing a new kernel without shutting down the X server...
there is a chance that the mach64 has DMAs in flight to addresses that
are no long existing...

Dave.

On 3/1/07, TuskenTower <tuskentower at gmail.com> wrote:
> All,
> I am not sure how to present the information I have, so please bear
> with me.  I am also dealing with distribution released Xorg and not
> plain Xorg.  I am unfamiliar with the Xorg code and building Xorg.
>
> My problem is this:
> I am testing the a RHEL 5 beta release with kexec
> (http://lwn.net/Articles/15468/) and kdump
> (http://lwn.net/Articles/108595/).  When I use kexec/kdump from the
> GUI (Xorg running with the ati driver), the subsequent kernel crashes
> hard (no panic, nothing at all) and I have not been able to determine
> what is causing it.
>
> Here's the fun part, if I kexec/kdump from a VT or from a VESA GUI
> (Xorg + vesa driver) the machine will not crash.  If I use the serial
> line for the console without the video console in the subsequent
> kernel, it will not crash.
>
> >From what I have observed, the ati driver is doing something that the
> ES7000 platform does not handle very well.  I have just starting to
> read the changelogs based on the 6.9 release date.   I have done a
> diff of the source trees and assumed that the only code I need to look
> at is related to Mach64 and Mach64 initialization (is this assumption
> wrong?).
>
> >From reading the code, I can only see changes related to EXA and XAA,
> but I have no idea what those mean.  The code changes look fairly
> contained, but I was hoping someone might know what could cause
> problems (I think I saw an APIC error reported somewhere).
>
> I have not compiled the Xorg ati driver yet to drop in some printks.
> If any of you have any suggestions (no I have not searched for Xorg
> driver debugging tips yet), please let me know.  Or at the very least
> punt (http://members.tripod.com/~tammy_lynn/gar940-1.gif) me in the
> right direction.
>
> thanks,
> Amul
>
> Configuration:
> SuSE Linux Enterprise Server 10
> Xorg ati driver source seems to map directly to X11R6.9.0 (with some
> differences in Radeon code)
> Arch: x86_64
> Xorg.0.log:
>   X Window System Version 6.9.0
>   Release Date: 21 December 2005
>   X Protocol Version 11, Revision 0, Release 6.9
>   Build Operating System: SuSE Linux [ELF] SuSE
>
> RedHat Enterprise Linux 5 (beta)
> Xorg ati driver source of the Xserver seems to match Xorg 7.2 release
> of the ati driver X11R7.2-6.6.3 (with some differences in the Radeon
> code)
> Arch: x86_64
> Xorg.0.log:
>   X Window System Version 7.1.1
>   Release Date: 12 May 2006
>   X Protocol Version 11, Revision 0, Release 7.1.1
>   Build Operating System: Linux 2.6.9-34.ELsmp x86_64 Red Hat, Inc.
>
> Hardware:
> Unisys ES7000, any configuration from 4 to 32 processors (dual-core
> and/or hyper threading) with 64GB to 256GB RAM.  Using a Rage Mobility
> chipset, lspci output
> 01:01.0 VGA compatible controller: ATI Technologies Inc Rage Mobility
> P/M (rev 64)
> This card is sitting behind an Intel ICH4 bridge.
> 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 82)
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>