drm/arm/malidp:- Writeback framebuffer does not support any modifiers

In malidp, the writeback pipeline does not support writing crtc output
to a framebuffer with modifiers ie the memory writeback content is
devoid of any compression or tiling, etc.
So we have added a commit check in memory writeback encoder helper function
to validate if the framebuffer has any modifier and if so, return EINVAL.

Changes since v3 (series):
- Added the ack
- Rebased on the latest drm-misc-next

Signed-off-by: Ayan Kumar halder <ayan.halder@arm.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Link: https://patchwork.freedesktop.org/patch/291765/?series=57895&rev=1

drivers/gpu/drm/arm/malidp_mw.c

@@ -141,6 +141,11 @@ malidp_mw_encoder_atomic_check(struct drm_encoder *encoder,
 		return -EINVAL;
 	}
 
+	if (fb->modifier) {
+		DRM_DEBUG_KMS("Writeback framebuffer does not support modifiers\n");
+		return -EINVAL;
+	}
+
 	mw_state->format =
 		malidp_hw_get_format_id(&malidp->dev->hw->map, SE_MEMWRITE,
 					fb->format->format, !!fb->modifier);