From 6c276e5d2c0ee362e4b860845401e095773fad7f Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Thu, 13 Jan 2022 11:30:42 +0000
Subject: [PATCH] drm/vc4: Disable Gamma control on HVS5 due to issues
 writing the table

Still under investigation, but the conditions under which the HVS
will accept values written to the gamma PWL are not straightforward.

Disable gamma on HVS5 again until it can be resolved to avoid
gamma being enabled with an incorrect table.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/gpu/drm/vc4/vc4_crtc.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -1182,15 +1182,9 @@ int vc4_crtc_init(struct drm_device *drm
 
 	if (!vc4->hvs->hvs5) {
 		drm_mode_crtc_set_gamma_size(crtc, ARRAY_SIZE(vc4_crtc->lut_r));
-	} else {
-		/* This is a lie for hvs5 which uses a 16 point PWL, but it
-		 * allows for something smarter than just 16 linearly spaced
-		 * segments. Conversion is done in vc5_hvs_update_gamma_lut.
-		 */
-		drm_mode_crtc_set_gamma_size(crtc, 256);
+		drm_crtc_enable_color_mgmt(crtc, 0, false, crtc->gamma_size);
 	}
 
-	drm_crtc_enable_color_mgmt(crtc, 0, false, crtc->gamma_size);
 
 	if (!vc4->hvs->hvs5) {
 		/* We support CTM, but only for one CRTC at a time. It's therefore
