[Mesa-dev] [PATCH] Better explain why we are lowering the num_tile_pipes value for TAHITI

[Michel Dänzer]

On 10.02.2016 10:11, Alexandre Demers wrote:
> Signed-off-by: Alexandre Demers <alexandre.f.demers at gmail.com>
> ---
>  src/gallium/winsys/radeon/drm/radeon_drm_winsys.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
> index 49c310c..aab81f9 100644
> --- a/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
> +++ b/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c
> @@ -405,8 +405,9 @@ static boolean do_winsys_init(struct radeon_drm_winsys *ws)
>              radeon_get_drm_value(ws->fd, RADEON_INFO_NUM_TILE_PIPES, NULL,
>                                   &ws->info.num_tile_pipes);
>  
> -            /* The kernel returns 12 for some cards for an unknown reason.
> -             * I thought this was supposed to be a power of two.
> +            /* Tahiti have a max_tile_pipes of 12 exceptionally. However, we 
> +             * work with power of two, so let's set it to the nearest power of 
> +             * two value.
>               */

Not sure that's better I'm afraid. It doesn't look like 12 is actually a
possible hardware configuration, it might simply be a kernel driver bug.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer