Forwarding this bug from Ubuntu reporter Jamie Strandboge:
Due to bug #26302, KMS seems to be broken on this hardware, so we're considering blacklisting this pci id to use UMS. However, with UMS instead of KMS, the screen suffers corruption when compositing is used.
This might be the old "Random screen corruption with 3D on XAA", however it appears the driver is opting for XAA rather than EXA as the default in this circumstance so that seems suboptimal. The user also tried forcing the hardware to use EXA but found it resulted in unacceptably slow performance.
The only known stable configuration for the radeon 7500 is XAA/metacity/RenderAccel off/no KMS).
This has been tested against Ubuntu 2.6.32-16.24-generic which contains the 2.6.33 drm backported, as airlied recommended.
In trying workarounds for LP bug #507148 (fdo #26302) I disabled KMS by booting with radeon.modeset=0. When I logged in compiz was enabled, but opening applications resulted in garbled parts of the screen. See attached screenshot.
Date: Thu Jan 28 13:52:56 2010
DistroRelease: Ubuntu 10.04
DkmsStatus: Error: [Errno 2] No such file or directory
Bus 004 Device 002: ID 0483:2016 SGS Thomson Microelectronics Fingerprint Reader
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: IBM 2378RRU
Package: xorg 1:7.5+1ubuntu2
no product info available
no product info available
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-11-generic root=UUID=0c1cec18-6655-4ef5-8c03-2009d66c50e2 ro splash quiet radeon.modeset=0
ProcVersionSignature: Ubuntu 2.6.32-11.15-generic
Uname: Linux 2.6.32-11-generic i686
dmi.bios.version: 1RETDRWW (3.23 )
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.version: Not Available
dmi.product.version: ThinkPad T42
architecture: i686kernel: 2.6.32-11-generic
01:00.0 VGA compatible controller : ATI Technologies Inc Radeon Mobility M7 LW [Radeon Mobility 7500] [1002:4c57]
Subsystem: IBM Device [1014:0530]
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isn't KMS + EXA + metacity stable?
I've gone ahead and disabled XAA render accel, it's been broken in the xserver for a while now.
> isn't KMS + EXA + metacity stable?
Jamie was saying that this particular configuration led to gpu lockups after a few hours of use. However I do not know if this configuration got re-tested with the 2.6.33 drm backport.
Jamie, you indicated the lockup issue still exists with KMS/XAA/compiz, and the compiz crash still occurs for KMS/EXA/compiz. Can you confirm that the KMS/EXA/metacity combo works, or does it still freeze after a few hours?
XAA/metacity/RenderAccel off/no KMS has been the only stable configuration for my system. KMS/EXA/metacity locks up, though not as often as with compiz. When I retested everything with the recent .33 backported DRM, I did not specifically test KMS/EXA/metacity since KMS/EXA/compiz was still broken.
I lent my laptop to a member of Canonical's kernel team for testing fixes/reproducing. I can follow up with him to test this configuration if required.
(In reply to comment #9)
> XAA/metacity/RenderAccel off/no KMS has been the only stable configuration for
> my system. KMS/EXA/metacity locks up, though not as often as with compiz. When
> I retested everything with the recent .33 backported DRM, I did not
> specifically test KMS/EXA/metacity since KMS/EXA/compiz was still broken.
Do the patches in bug 26302 help with kms?
The patches from 26302 *do* help. Quoting me from that bug:
"These patches resolve this issue completely. After a lot of automated testing
and many hours of real world use with up to date packages that include these
fixes, it no longer crashes. Thanks to everyone who helped fix this. :)
From our kernel changelog:
[ Upstream Kernel Changes ]
* drm/radeon/bo: add some fallback placements for VRAM only objects.
- LP: #507148
* drm/radeon/kms: don't print error on -ERESTARTSYS.
- LP: #507148
I've not specifically testing KMS with XAA, but KMS with EXA/compiz works well now.
(In reply to comment #11)
> I've not specifically testing KMS with XAA, but KMS with EXA/compiz works well
XAA doesn't work with kms, so there's nothing to test :)