[Intel-gfx] [PATCH 1/3] drm/intel: Store full 16 bits of colors passed to gamma LUT

[Peter Clifton]

Store the full precision, even if we only use the high byte
when programming the palette registers.
---
 drivers/gpu/drm/i915/intel_display.c |   30 +++++++++++++++---------------
 drivers/gpu/drm/i915/intel_drv.h     |    2 +-
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 006e5a5..456f738 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3452,9 +3452,9 @@ void intel_crtc_load_lut(struct drm_crtc *crtc)
 
 	for (i = 0; i < 256; i++) {
 		I915_WRITE(pal_reg + 4 * i,
-			   (intel_crtc->lut_r[i] << 16) |
-			   (intel_crtc->lut_g[i] << 8) |
-			   intel_crtc->lut_b[i]);
+			   ((intel_crtc->lut_r[i] >> 8) << 16) |
+			   ((intel_crtc->lut_g[i] >> 8) << 8) |
+			   (intel_crtc->lut_b[i] >> 8));
 	}
 }
 
@@ -3609,9 +3609,9 @@ void intel_crtc_fb_gamma_set(struct drm_crtc *crtc, u16 red, u16 green,
 {
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 
-	intel_crtc->lut_r[regno] = red >> 8;
-	intel_crtc->lut_g[regno] = green >> 8;
-	intel_crtc->lut_b[regno] = blue >> 8;
+	intel_crtc->lut_r[regno] = red;
+	intel_crtc->lut_g[regno] = green;
+	intel_crtc->lut_b[regno] = blue;
 }
 
 void intel_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
@@ -3619,9 +3619,9 @@ void intel_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
 {
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 
-	*red = intel_crtc->lut_r[regno] << 8;
-	*green = intel_crtc->lut_g[regno] << 8;
-	*blue = intel_crtc->lut_b[regno] << 8;
+	*red = intel_crtc->lut_r[regno];
+	*green = intel_crtc->lut_g[regno];
+	*blue = intel_crtc->lut_b[regno];
 }
 
 static void intel_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
@@ -3634,9 +3634,9 @@ static void intel_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
 		return;
 
 	for (i = 0; i < 256; i++) {
-		intel_crtc->lut_r[i] = red[i] >> 8;
-		intel_crtc->lut_g[i] = green[i] >> 8;
-		intel_crtc->lut_b[i] = blue[i] >> 8;
+		intel_crtc->lut_r[i] = red[i];
+		intel_crtc->lut_g[i] = green[i];
+		intel_crtc->lut_b[i] = blue[i];
 	}
 
 	intel_crtc_load_lut(crtc);
@@ -4294,9 +4294,9 @@ static void intel_crtc_init(struct drm_device *dev, int pipe)
 	intel_crtc->pipe = pipe;
 	intel_crtc->plane = pipe;
 	for (i = 0; i < 256; i++) {
-		intel_crtc->lut_r[i] = i;
-		intel_crtc->lut_g[i] = i;
-		intel_crtc->lut_b[i] = i;
+		intel_crtc->lut_r[i] = i << 8 | i;
+		intel_crtc->lut_g[i] = i << 8 | i;
+		intel_crtc->lut_b[i] = i << 8 | i;
 	}
 
 	/* Swap pipes & planes for FBC on pre-965 */
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 3dcf5cc..6f09806 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -143,7 +143,7 @@ struct intel_crtc {
 	enum plane plane;
 	struct drm_gem_object *cursor_bo;
 	uint32_t cursor_addr;
-	u8 lut_r[256], lut_g[256], lut_b[256];
+	u16 lut_r[256], lut_g[256], lut_b[256];
 	int dpms_mode;
 	bool busy; /* is scanout buffer being updated frequently? */
 	struct timer_list idle_timer;
-- 
1.7.0.4