Re: [PATCH v2 2/3] drm/radeon: Restore GART table contents after pinning it in VRAM

["Christian König" <deathsimple@vodafone.de>]

Am 22.01.2015 um 08:30 schrieb Michel Dänzer:
> From: Michel Dänzer <michel.daenzer@amd.com>
>
> The GART table BO has to be moved out of VRAM for suspend/resume. Any
> updates to the GART table during that time were silently dropped without
> this change. This caused GPU lockups on resume in some cases, see the bug
> reports referenced below.
>
> This might also make GPU reset more robust in some cases, as we no longer
> rely on the GART table in VRAM being preserved across the GPU
> lockup/reset.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85204
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86267
> Cc: stable@vger.kernel.org
> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
> ---
>
> v2: Add logic to radeon_gart_table_vram_pin directly instead of reinstating
>      radeon_gart_restore function
>
>   drivers/gpu/drm/radeon/radeon_gart.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_gart.c b/drivers/gpu/drm/radeon/radeon_gart.c
> index a530932..0c8c739 100644
> --- a/drivers/gpu/drm/radeon/radeon_gart.c
> +++ b/drivers/gpu/drm/radeon/radeon_gart.c
> @@ -163,6 +163,14 @@ int radeon_gart_table_vram_pin(struct radeon_device *rdev)
>   	r = radeon_bo_kmap(rdev->gart.robj, &rdev->gart.ptr);
>   	if (r)
>   		radeon_bo_unpin(rdev->gart.robj);
> +	else {

I would add a comment why we do this here.

> +		int i;
> +
> +		for (i = 0; i < rdev->gart.num_gpu_pages; i++)
> +			radeon_gart_set_page(rdev, i, rdev->gart.pages_entry[i]);
> +		mb();
> +		radeon_gart_tlb_flush(rdev);

That TLB flush won't work correctly because the table_addr isn't up to 
date yet.

> +	}
>   	radeon_bo_unreserve(rdev->gart.robj);
>   	rdev->gart.table_addr = gpu_addr;
It's updated here instead. Maybe completely drop the local gpu_addr 
variable and update the table_addr directly instead.

Christian.

>   	return r;

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