Added a check for the radeon ring buffer write index in r600.c which
reads 0xffffffff on resume. This results in an Oops during
radeon_ring_write. Masking the value averts this.
This problem is not seen to be fixed in 3.0 r600.c as well.
Detailed analysis of the problem can be found at -
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/820746/
---
BUG: unable to handle kernel paging request at fa501ffc - Oops at
r600_cp_start+0x48/0x380 in r600_cp_resume+0x345/0x580 [radeon]
drivers/gpu/drm/radeon/r600.c
--- linux-2.6.38/drivers/gpu/drm/radeon/r600.c.orig 2011-08-05
15:39:40.824612700 +0530
+++ linux-2.6.38/drivers/gpu/drm/radeon/r600.c 2011-08-08
05:29:21.744417857 +0530
@@ -2218,6 +2218,8 @@ int r600_cp_resume(struct radeon_device
rdev->cp.rptr = RREG32(CP_RB_RPTR);
rdev->cp.wptr = RREG32(CP_RB_WPTR);
+ /* protect against crazy HW on resume */
+ rdev->cp.wptr &= rdev->cp.ptr_mask;
r600_cp_start(rdev);
rdev->cp.ready = true;
Developer's Certificate of Origin 1.1
By making a contribution to this project, I certify that:
(a) The contribution was created in whole or in part by me and I
have the right to submit it under the open source license
indicated in the file; or
(b) The contribution is based upon previous work that, to the best
of my knowledge, is covered under an appropriate open source
license and I have the right under that license to submit that
work with modifications, whether created in whole or in part
by me, under the same open source license (unless I am
permitted to submit under a different license), as indicated
in the file; or
(c) The contribution was provided directly to me by some other
person who certified (a), (b) or (c) and I have not modified
it.
(d) I understand and agree that this project and the contribution
are public and that a record of the contribution (including all
personal information I submit with it, including my sign-off) is
maintained indefinitely and may be redistributed consistent with
this project or the open source license(s) involved.
Signed-off-by: A R Karthick <a.r.karthick@xxxxxxxxx>
Reported-by: Mayank Rungta <mr.mynk@xxxxxxxxx>
Tested-by: Mayank Rungta <mr.mynk@xxxxxxxxx>
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