drm/mgag200: Fix gamma lut not initialized for G200ER, G200EV, G200SE

When mgag200 switched from simple KMS to regular atomic helpers,
the initialization of the gamma settings was lost.
This leads to a black screen, if the bios/uefi doesn't use the same
pixel color depth.
This has been fixed with commit ad81e234 ("drm/mgag200: Fix gamma
lut not initialized.") for most G200, but G200ER, G200EV, G200SE use
their own version of crtc_helper_atomic_enable() and need to be fixed
too.

Fixes: 1baf9127 ("drm/mgag200: Replace simple-KMS with regular atomic helpers")
Cc: <stable@vger.kernel.org> #v6.1+
Reported-by: Roger Sewell <roger.sewell@cantab.net>
Suggested-by: Roger Sewell <roger.sewell@cantab.net>
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20231214163849.359691-1-jfalempe@redhat.com

drivers/gpu/drm/mgag200/mgag200_drv.h

@@ -392,6 +392,11 @@ void mgag200_primary_plane_helper_atomic_disable(struct drm_plane *plane,
 	.destroy = drm_plane_cleanup, \
 	DRM_GEM_SHADOW_PLANE_FUNCS
 
+void mgag200_crtc_set_gamma_linear(struct mga_device *mdev, const struct drm_format_info *format);
+void mgag200_crtc_set_gamma(struct mga_device *mdev,
+			    const struct drm_format_info *format,
+			    struct drm_color_lut *lut);
+
 enum drm_mode_status mgag200_crtc_helper_mode_valid(struct drm_crtc *crtc,
 						    const struct drm_display_mode *mode);
 int mgag200_crtc_helper_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *new_state);

drivers/gpu/drm/mgag200/mgag200_g200er.c

@@ -202,6 +202,11 @@ static void mgag200_g200er_crtc_helper_atomic_enable(struct drm_crtc *crtc,
 
 	mgag200_g200er_reset_tagfifo(mdev);
 
+	if (crtc_state->gamma_lut)
+		mgag200_crtc_set_gamma(mdev, format, crtc_state->gamma_lut->data);
+	else
+		mgag200_crtc_set_gamma_linear(mdev, format);
+
 	mgag200_enable_display(mdev);
 
 	if (funcs->enable_vidrst)

drivers/gpu/drm/mgag200/mgag200_g200ev.c

@@ -203,6 +203,11 @@ static void mgag200_g200ev_crtc_helper_atomic_enable(struct drm_crtc *crtc,
 
 	mgag200_g200ev_set_hiprilvl(mdev);
 
+	if (crtc_state->gamma_lut)
+		mgag200_crtc_set_gamma(mdev, format, crtc_state->gamma_lut->data);
+	else
+		mgag200_crtc_set_gamma_linear(mdev, format);
+
 	mgag200_enable_display(mdev);
 
 	if (funcs->enable_vidrst)

drivers/gpu/drm/mgag200/mgag200_g200se.c

@@ -334,6 +334,11 @@ static void mgag200_g200se_crtc_helper_atomic_enable(struct drm_crtc *crtc,
 
 	mgag200_g200se_set_hiprilvl(mdev, adjusted_mode, format);
 
+	if (crtc_state->gamma_lut)
+		mgag200_crtc_set_gamma(mdev, format, crtc_state->gamma_lut->data);
+	else
+		mgag200_crtc_set_gamma_linear(mdev, format);
+
 	mgag200_enable_display(mdev);
 
 	if (funcs->enable_vidrst)

drivers/gpu/drm/mgag200/mgag200_mode.c

@@ -28,8 +28,8 @@
  * This file contains setup code for the CRTC.
  */
 
-static void mgag200_crtc_set_gamma_linear(struct mga_device *mdev,
-					  const struct drm_format_info *format)
+void mgag200_crtc_set_gamma_linear(struct mga_device *mdev,
+				   const struct drm_format_info *format)
 {
 	int i;
 
@@ -65,9 +65,9 @@ static void mgag200_crtc_set_gamma_linear(struct mga_device *mdev,
 	}
 }
 
-static void mgag200_crtc_set_gamma(struct mga_device *mdev,
-				   const struct drm_format_info *format,
-				   struct drm_color_lut *lut)
+void mgag200_crtc_set_gamma(struct mga_device *mdev,
+			    const struct drm_format_info *format,
+			    struct drm_color_lut *lut)
 {
 	int i;