isl: Let isl_surf_init's caller set the exact row pitch (v2)

The caller does so by setting the new field
isl_surf_init_info::row_pitch.

v2: Validate the requested row_pitch.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> (v2)

src/intel/isl/isl.c

@@ -1118,10 +1118,22 @@ isl_calc_row_pitch(const struct isl_device *dev,
    const uint32_t alignment =
       isl_calc_row_pitch_alignment(surf_info, tile_info);
 
-   const uint32_t row_pitch =
+   const uint32_t min_row_pitch =
       isl_calc_min_row_pitch(dev, surf_info, tile_info, phys_slice0_sa,
                              alignment);
 
+   uint32_t row_pitch = min_row_pitch;
+
+   if (surf_info->row_pitch != 0) {
+      row_pitch = surf_info->row_pitch;
+
+      if (row_pitch < min_row_pitch)
+         return false;
+
+      if (row_pitch % alignment != 0)
+         return false;
+   }
+
    const uint32_t row_pitch_tiles = row_pitch / tile_info->phys_extent_B.width;
 
    if (row_pitch == 0)

src/intel/isl/isl.h

@@ -813,6 +813,12 @@ struct isl_surf_init_info {
    /** Lower bound for isl_surf::pitch, in bytes. */
    uint32_t min_pitch;
 
+   /**
+    * Exact value for isl_surf::row_pitch. Ignored if zero.  isl_surf_init()
+    * will fail if this is misaligned or out of bounds.
+    */
+   uint32_t row_pitch;
+
    isl_surf_usage_flags_t usage;
 
    /** Flags that alter how ISL selects isl_surf::tiling.  */