[Mesa-dev] [PATCH 1/2] r600g, radeonsi: query the buffer domain from the kernel for DRI2 buffers

[Marek Olšák]

I know, but do you have a better idea? If the buffer isn't evicted, we
should get the correct placement. The code also respects placement of
Prime buffers, which should be in GTT. This is as close to the ideal
solution as it can possibly be. I don't think it can be any better
with our kernel interface.

Marek

On Wed, Feb 5, 2014 at 8:37 AM, Michel Dänzer <michel at daenzer.net> wrote:
> On Mit, 2014-02-05 at 00:01 +0100, Marek Olšák wrote:
>> From: Marek Olšák <marek.olsak at amd.com>
>>
>> Better then guessing it.
>>
>> Yeah we have had this query for a long time...
>
> [...]
>
>> diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_bo.c b/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
>> index 2ac060b..7c59f26 100644
>> --- a/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
>> +++ b/src/gallium/winsys/radeon/drm/radeon_drm_bo.c
>> @@ -201,6 +201,28 @@ static boolean radeon_bo_is_busy(struct pb_buffer *_buf,
>>      }
>>  }
>>
>> +static enum radeon_bo_domain radeon_bo_get_current_domain(struct pb_buffer *_buf)
>> +{
>> +    struct radeon_bo *bo = get_radeon_bo(_buf);
>> +    struct drm_radeon_gem_busy args;
>> +
>> +    memset(&args, 0, sizeof(args));
>> +    args.handle = bo->handle;
>> +
>> +    drmCommandWriteRead(bo->rws->fd, DRM_RADEON_GEM_BUSY,
>> +                        &args, sizeof(args));
>> +
>> +    /* Zero domains the driver doesn't understand. */
>> +    args.domain &= ~(RADEON_GEM_DOMAIN_VRAM | RADEON_GEM_DOMAIN_GTT);
>> +
>> +    /* If no domain is set, we must set something... */
>> +    if (!args.domain)
>> +        args.domain = RADEON_GEM_DOMAIN_VRAM | RADEON_GEM_DOMAIN_GTT;
>> +
>> +    /* GEM domains and winsys domains are defined the same. */
>> +    return args.domain;
>> +}
>
> The problem with this is that DRM_RADEON_GEM_BUSY doesn't say where the
> BO is supposed to be, but where it happens to be right now. E.g. it
> could return GTT for a BO that's supposed to be in VRAM but was evicted
> (or couldn't get into VRAM in the first place).
>
>
> --
> Earthling Michel Dänzer            |                  http://www.amd.com
> Libre software enthusiast          |                Mesa and X developer
>