radeon, kdb, kms: Save and restore the LUT on atomic KMS enter/exit

When changing VTs non-atomically the kernel works in conjunction with
the Xserver in user space and receives the LUT information from the
Xserver via a system call.  When changing modes atomically for kdb,
this information must be saved and restored without disturbing user
space as if nothing ever happened.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
CC: David Airlie <airlied@linux.ie>
CC: dri-devel@lists.freedesktop.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_display.c

@@ -138,6 +138,38 @@ void radeon_crtc_load_lut(struct drm_crtc *crtc)
 		legacy_crtc_load_lut(crtc);
 }
 
+void radeon_crtc_save_lut(struct drm_crtc *crtc)
+{
+	struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
+	int i;
+
+	if (!crtc->enabled)
+		return;
+
+	for (i = 0; i < 256; i++) {
+		radeon_crtc->lut_r_copy[i] = radeon_crtc->lut_r[i];
+		radeon_crtc->lut_g_copy[i] = radeon_crtc->lut_g[i];
+		radeon_crtc->lut_b_copy[i] = radeon_crtc->lut_b[i];
+	}
+}
+
+void radeon_crtc_restore_lut(struct drm_crtc *crtc)
+{
+	struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
+	int i;
+
+	if (!crtc->enabled)
+		return;
+
+	for (i = 0; i < 256; i++) {
+		radeon_crtc->lut_r[i] = radeon_crtc->lut_r_copy[i];
+		radeon_crtc->lut_g[i] = radeon_crtc->lut_g_copy[i];
+		radeon_crtc->lut_b[i] = radeon_crtc->lut_b_copy[i];
+	}
+
+	radeon_crtc_load_lut(crtc);
+}
+
 /** Sets the color ramps on behalf of fbcon */
 void radeon_crtc_fb_gamma_set(struct drm_crtc *crtc, u16 red, u16 green,
 			      u16 blue, int regno)

drivers/gpu/drm/radeon/radeon_legacy_crtc.c

@@ -355,6 +355,11 @@ int radeon_crtc_set_base_atomic(struct drm_crtc *crtc,
 				struct drm_framebuffer *fb,
 				int x, int y, int enter)
 {
+	if (enter)
+		radeon_crtc_save_lut(crtc);
+	else
+		radeon_crtc_restore_lut(crtc);
+
 	return radeon_crtc_do_set_base(crtc, fb, x, y, 1);
 }
 

drivers/gpu/drm/radeon/radeon_mode.h

@@ -267,6 +267,7 @@ struct radeon_crtc {
 	struct drm_crtc base;
 	int crtc_id;
 	u16 lut_r[256], lut_g[256], lut_b[256];
+	u16 lut_r_copy[256], lut_g_copy[256], lut_b_copy[256];
 	bool enabled;
 	bool can_tile;
 	uint32_t crtc_offset;
@@ -512,6 +513,8 @@ extern int atombios_get_encoder_mode(struct drm_encoder *encoder);
 extern void radeon_encoder_set_active_device(struct drm_encoder *encoder);
 
 extern void radeon_crtc_load_lut(struct drm_crtc *crtc);
+extern void radeon_crtc_save_lut(struct drm_crtc *crtc);
+extern void radeon_crtc_restore_lut(struct drm_crtc *crtc);
 extern int atombios_crtc_set_base(struct drm_crtc *crtc, int x, int y,
 				   struct drm_framebuffer *old_fb);
 extern int atombios_crtc_set_base_atomic(struct drm_crtc *crtc,