From: "Michel Dänzer" <michel@daenzer.net>
To: Mayank Rungta <mr.mynk@gmail.com>
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
yakui.zhao@intel.com, "A.R Karthick" <a.r.karthick@gmail.com>,
karthick.linuxdreamer@gmail.com
Subject: Re: [PATCH 2.6.38-10-generic] device driver: fix oops in radeon driver due to incorrect value from hardware
Date: Wed, 10 Aug 2011 11:24:31 +0200 [thread overview]
Message-ID: <1312968271.14630.189.camel@thor.local> (raw)
In-Reply-To: <4E417AF8.7090202@gmail.com>
On Die, 2011-08-09 at 23:52 +0530, Mayank Rungta wrote:
> 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;
The indentation of the lines you're adding doesn't match the surrounding
lines.
Although the same workaround is already in r100.c, I wonder if we
shouldn't rather try and eliminate all reads from the CP_RB_WPTR
register, at least other than for debugging purposes. Alex, what do you
think?
Otherwise, this should probably be added in evergreen.c as well.
> Developer's Certificate of Origin 1.1
>
> [...]
No need to include all this text, just the *-by: tags are enough.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Debian, X and DRI developer
WARNING: multiple messages have this Message-ID (diff)
From: "Michel Dänzer" <michel@daenzer.net>
To: Mayank Rungta <mr.mynk@gmail.com>
Cc: "A.R Karthick" <a.r.karthick@gmail.com>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
karthick.linuxdreamer@gmail.com
Subject: Re: [PATCH 2.6.38-10-generic] device driver: fix oops in radeon driver due to incorrect value from hardware
Date: Wed, 10 Aug 2011 11:24:31 +0200 [thread overview]
Message-ID: <1312968271.14630.189.camel@thor.local> (raw)
In-Reply-To: <4E417AF8.7090202@gmail.com>
On Die, 2011-08-09 at 23:52 +0530, Mayank Rungta wrote:
> 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;
The indentation of the lines you're adding doesn't match the surrounding
lines.
Although the same workaround is already in r100.c, I wonder if we
shouldn't rather try and eliminate all reads from the CP_RB_WPTR
register, at least other than for debugging purposes. Alex, what do you
think?
Otherwise, this should probably be added in evergreen.c as well.
> Developer's Certificate of Origin 1.1
>
> [...]
No need to include all this text, just the *-by: tags are enough.
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Debian, X and DRI developer
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next prev parent reply other threads:[~2011-08-10 9:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-09 18:22 [PATCH 2.6.38-10-generic] device driver: fix oops in radeon driver due to incorrect value from hardware Mayank Rungta
2011-08-10 9:24 ` Michel Dänzer [this message]
2011-08-10 9:24 ` Michel Dänzer
2011-08-10 9:46 ` Mayank Rungta
2011-08-10 13:27 ` Alex Deucher
2011-09-08 13:50 ` Michel Dänzer
2011-09-08 13:50 ` Michel Dänzer
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