[Mesa-dev] [PATCH 5/8] i965/dri: Handle the linear fb modifier

[Jason Ekstrand]

On Tue, Mar 21, 2017 at 1:45 PM, Ben Widawsky <ben at bwidawsk.net> wrote:

> At image creation create a path for dealing with the linear modifier.
> This works exactly like the old usage flags where __DRI_IMAGE_USE_LINEAR
> was specified.
>
> During development of this patch series, it was decided that a lack of
> modifier was an insufficient way to express the required modifiers. As a
> result, 0 was repurposed to mean a modifier for a LINEAR layout.
>
> NOTE: This patch was added for v3 of the patch series.
>
> v2: Rework the algorithm for modifier selection to go from a bitmask
> based selection to this priority value.
>
> Requested-by: Jason Ekstrand <jason at jlekstrand.net>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
> ---
>  src/mesa/drivers/dri/i965/intel_screen.c | 55
> +++++++++++++++++++++++++-------
>  1 file changed, 44 insertions(+), 11 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/intel_screen.c
> b/src/mesa/drivers/dri/i965/intel_screen.c
> index 26ab5a8e19..8ba90f0a0c 100644
> --- a/src/mesa/drivers/dri/i965/intel_screen.c
> +++ b/src/mesa/drivers/dri/i965/intel_screen.c
> @@ -45,6 +45,10 @@
>  #define DRM_FORMAT_MOD_INVALID ((1ULL<<56) - 1)
>  #endif
>
> +#ifndef DRM_FORMAT_MOD_LINEAR
> +#define DRM_FORMAT_MOD_LINEAR 0
> +#endif
> +
>  static const __DRIconfigOptionsExtension brw_config_options = {
>     .base = { __DRI_CONFIG_OPTIONS, 1 },
>     .xml =
> @@ -511,13 +515,36 @@ intel_destroy_image(__DRIimage *image)
>     free(image);
>  }
>
> +enum modifier_priority {
> +   MODIFIER_PRIORITY_INVALID = 0,
> +   MODIFIER_PRIORITY_LINEAR,
> +};
> +
> +const uint64_t priority_to_modifier[] = {
> +   [MODIFIER_PRIORITY_INVALID] = DRM_FORMAT_MOD_INVALID,
> +   [MODIFIER_PRIORITY_LINEAR] = DRM_FORMAT_MOD_LINEAR,
> +};
> +
>  static uint64_t
>  select_best_modifier(struct gen_device_info *devinfo,
>                       const uint64_t *modifiers,
>                       const unsigned count)
>  {
> -   /* Modifiers are not supported by this DRI driver */
> -   return DRM_FORMAT_MOD_INVALID;
> +
> +   enum modifier_priority prio = MODIFIER_PRIORITY_INVALID;
> +
> +   for (int i = 0; i < count; i++) {
> +      switch (modifiers[i]) {
> +      case DRM_FORMAT_MOD_LINEAR:
> +         prio = MAX2(prio, MODIFIER_PRIORITY_LINEAR);
> +         break;
> +      case DRM_FORMAT_MOD_INVALID:
> +      default:
> +         unreachable("Invalid modifiers specified\n");
>

How'd this sneak back in?  I think you want to just fall through and
continue on to the next loop iteration in this case.


> +      }
> +   }
> +
> +   return priority_to_modifier[prio];
>  }
>
>  static __DRIimage *
> @@ -530,7 +557,10 @@ intel_create_image_common(__DRIscreen *dri_screen,
>  {
>     __DRIimage *image;
>     struct intel_screen *screen = dri_screen->driverPrivate;
> -   uint32_t tiling;
> +   /* Historically, X-tiled was the default, and so lack of modifier means
> +    * X-tiled.
> +    */
> +   uint32_t tiling = I915_TILING_X;
>     int cpp;
>     unsigned long pitch;
>
> @@ -541,15 +571,17 @@ intel_create_image_common(__DRIscreen *dri_screen,
>     assert(!(use && count));
>
>     uint64_t modifier = select_best_modifier(&screen->devinfo, modifiers,
> count);
> -   assert(modifier == DRM_FORMAT_MOD_INVALID);
> -
> -   if (modifier == DRM_FORMAT_MOD_INVALID && modifiers)
> -      return NULL;
> +   switch (modifier) {
> +   case DRM_FORMAT_MOD_LINEAR:
> +      tiling = I915_TILING_NONE;
> +      break;
> +   case DRM_FORMAT_MOD_INVALID:
> +      if (modifiers)
> +         return NULL;
> +   default:
> +         break;
> +   }
>
> -   /* Historically, X-tiled was the default, and so lack of modifier means
> -    * X-tiled.
> -    */
> -   tiling = I915_TILING_X;
>     if (use & __DRI_IMAGE_USE_CURSOR) {
>        if (width != 64 || height != 64)
>          return NULL;
> @@ -574,6 +606,7 @@ intel_create_image_common(__DRIscreen *dri_screen,
>     image->width = width;
>     image->height = height;
>     image->pitch = pitch;
> +   image->modifier = modifier;
>
>     return image;
>  }
> --
> 2.12.0
>
>
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