drm/i915/adl_p: Require a minimum of 8 tiles stride for DPT FBs

The specification only requires DPT FB strides to be POT aligned, but
there seems to be also a minimum of 8 stride tile requirement. Scanning
out FBs with < 8 stride tiles will result in pipe faults (even though
the stride is POT aligned).
Signed-off-by: Imre Deak <imre.deak@intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210506161930.309688-10-imre.deak@intel.com

drivers/gpu/drm/i915/display/intel_fb.c

@@ -601,7 +601,11 @@ plane_view_dst_stride_tiles(const struct intel_framebuffer *fb, int color_plane,
 			    unsigned int pitch_tiles)
 {
 	if (intel_fb_needs_pot_stride_remap(fb))
-		return roundup_pow_of_two(pitch_tiles);
+		/*
+		 * ADL_P, the only platform needing a POT stride has a minimum
+		 * of 8 stride tiles.
+		 */
+		return roundup_pow_of_two(max(pitch_tiles, 8u));
 	else
 		return pitch_tiles;
 }