On 29.08.2014 00:01, Alex Deucher wrote:
> On Thu, Aug 28, 2014 at 4:57 AM, Christian König
> <deathsimple@xxxxxxxxxxx> wrote:
>> Am 28.08.2014 um 08:56 schrieb Michel Dänzer:
>>
>>> From: Michel Dänzer <michel.daenzer@xxxxxxx>
>>>
>>> This flag is a hint that userspace expects the BO to be accessed by the
>>> CPU. We can use that hint to prevent such BOs from ever being stored in
>>> the CPU inaccessible part of VRAM.
>>>
>>> Signed-off-by: Michel Dänzer <michel.daenzer@xxxxxxx>
>>
>>
>> This patch is Reviewed-by: Christian König <christian.koenig@xxxxxxx>
>
> Applied to my -next tree.
Thanks!
>> I think we need a similar negative flags as well, e.g.
>> RADEON_GEM_NO_CPU_ACCESS.
>>
>> This way we can stop forcing buffers into the visible VRAM while pinning
>> them for scanout.
>
> How about the attached patch?
[...]
> diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
> index 09b039a..b71e8e0 100644
> --- a/drivers/gpu/drm/radeon/radeon_object.c
> +++ b/drivers/gpu/drm/radeon/radeon_object.c
> @@ -314,10 +314,14 @@ int radeon_bo_pin_restricted(struct radeon_bo *bo, u32 domain, u64 max_offset,
> unsigned lpfn = 0;
>
> /* force to pin into visible video ram */
> - if (bo->placements[i].flags & TTM_PL_FLAG_VRAM)
> - lpfn = bo->rdev->mc.visible_vram_size >> PAGE_SHIFT;
> - else
> + if (bo->placements[i].flags & TTM_PL_FLAG_VRAM) {
> + if (bo->flags & RADEON_GEM_NO_CPU_ACCESS)
> + lpfn = bo->rdev->mc.real_vram_size >> PAGE_SHIFT;
> + else
> + lpfn = bo->rdev->mc.visible_vram_size >> PAGE_SHIFT;
lpfn can be left at 0 if RADEON_GEM_NO_CPU_ACCESS is set, so this can
be simplified to:
if (!(bo->flags & RADEON_GEM_NO_CPU_ACCESS))
lpfn = bo->rdev->mc.visible_vram_size >> PAGE_SHIFT;
> diff --git a/include/uapi/drm/radeon_drm.h b/include/uapi/drm/radeon_drm.h
> index f755f20..d2346fd 100644
> --- a/include/uapi/drm/radeon_drm.h
> +++ b/include/uapi/drm/radeon_drm.h
> @@ -803,6 +803,8 @@ struct drm_radeon_gem_info {
> #define RADEON_GEM_GTT_WC (1 << 2)
> /* BO is expected to be accessed by the CPU */
> #define RADEON_GEM_CPU_ACCESS (1 << 3)
> +/* BO is expected to not be accessed by the CPU */
> +#define RADEON_GEM_NO_CPU_ACCESS (1 << 4)
I'd use stronger wording for this, e.g.
/* CPU access is not expected to work for this BO */
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
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