[PATCH] drm/i915: Correctly handle limited range YCbCr data on VLV/CHV

* [PATCH] drm/i915: Correctly handle limited range YCbCr data on VLV/CHV
@ 2016-07-21 19:17 ville.syrjala
  2016-07-22  6:47 ` ✗ Ro.CI.BAT: failure for " Patchwork
  0 siblings, 1 reply; 3+ messages in thread
From: ville.syrjala @ 2016-07-21 19:17 UTC (permalink / raw)
  To: intel-gfx; +Cc: Tang, Jun, stable

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Turns out the VLV/CHV fixed function sprite CSC expects full range
data as input. We've been feeding it limited range data to it all
along. To expand the data out to full range we'll use the color
correction registers (brightness, contrast, and saturation).

On CHV pipe B we were actually doing the right thing already because we
progammed the custom CSC matrix to do expect limited range input. Now
that well pre-expand the data out with the color correction unit, we
need to change the CSC matrix to operate with full range input instead.

This should make the sprite output of the other pipes match the sprite
output of pipe B reasonably well. Looking at the resulting pipe CRCs,
there can be a slight difference in the output, but as I don't know
the formula used by the fixed function CSC of the other pipes, I don't
think it's worth the effort to try to match the output exactly. It
might not even be possible due to difference in internal precision etc.

One slight caveat here is that the color correction registers are single
bufferred, so we should really be updating them during vblank, but we
still don't have a mechanism for that, so just toss in another FIXME.

Cc: "Tang, Jun" <jun.tang@intel.com>
Reported-by: "Tang, Jun" <jun.tang@intel.com>
Cc: stable@vger.kernel.org
Fixes: 7f1f3851feb0 ("drm/i915: sprite support for ValleyView v4")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h     | 10 ++++++
 drivers/gpu/drm/i915/intel_sprite.c | 62 ++++++++++++++++++++++++++++---------
 2 files changed, 57 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 8bfde75789f6..25223b1d9775 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -5385,6 +5385,12 @@ enum {
 #define _SPATILEOFF		(VLV_DISPLAY_BASE + 0x721a4)
 #define _SPACONSTALPHA		(VLV_DISPLAY_BASE + 0x721a8)
 #define   SP_CONST_ALPHA_ENABLE		(1<<31)
+#define _SPACLRC0		(VLV_DISPLAY_BASE + 0x721d0)
+#define   SP_CONTRAST(x)		((x) << 18) /* u3.6 */
+#define   SP_BRIGHTNESS(x)		((x) & 0xff) /* s8 */
+#define _SPACLRC1		(VLV_DISPLAY_BASE + 0x721d4)
+#define   SP_SH_SIN(x)			(((x) & 0x7ff) << 16) /* s4.7 */
+#define   SP_SH_COS(x)			(x) /* u3.7 */
 #define _SPAGAMC		(VLV_DISPLAY_BASE + 0x721f4)
 
 #define _SPBCNTR		(VLV_DISPLAY_BASE + 0x72280)
@@ -5398,6 +5404,8 @@ enum {
 #define _SPBKEYMAXVAL		(VLV_DISPLAY_BASE + 0x722a0)
 #define _SPBTILEOFF		(VLV_DISPLAY_BASE + 0x722a4)
 #define _SPBCONSTALPHA		(VLV_DISPLAY_BASE + 0x722a8)
+#define _SPBCLRC0		(VLV_DISPLAY_BASE + 0x722d0)
+#define _SPBCLRC1		(VLV_DISPLAY_BASE + 0x722d4)
 #define _SPBGAMC		(VLV_DISPLAY_BASE + 0x722f4)
 
 #define SPCNTR(pipe, plane) _MMIO_PIPE((pipe) * 2 + (plane), _SPACNTR, _SPBCNTR)
@@ -5411,6 +5419,8 @@ enum {
 #define SPKEYMAXVAL(pipe, plane) _MMIO_PIPE((pipe) * 2 + (plane), _SPAKEYMAXVAL, _SPBKEYMAXVAL)
 #define SPTILEOFF(pipe, plane) _MMIO_PIPE((pipe) * 2 + (plane), _SPATILEOFF, _SPBTILEOFF)
 #define SPCONSTALPHA(pipe, plane) _MMIO_PIPE((pipe) * 2 + (plane), _SPACONSTALPHA, _SPBCONSTALPHA)
+#define SPCLRC0(pipe, plane) _MMIO_PIPE((pipe) * 2 + (plane), _SPACLRC0, _SPBCLRC0)
+#define SPCLRC1(pipe, plane) _MMIO_PIPE((pipe) * 2 + (plane), _SPACLRC1, _SPBCLRC1)
 #define SPGAMC(pipe, plane) _MMIO_PIPE((pipe) * 2 + (plane), _SPAGAMC, _SPBGAMC)
 
 /*
diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 0de935ad01c2..7bea7859df8e 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -325,28 +325,28 @@ chv_update_csc(struct intel_plane *intel_plane, uint32_t format)
 		return;
 
 	/*
-	 * BT.601 limited range YCbCr -> full range RGB
+	 * BT.601 full range YCbCr -> full range RGB
 	 *
-	 * |r|   | 6537 4769     0|   |cr  |
-	 * |g| = |-3330 4769 -1605| x |y-64|
-	 * |b|   |    0 4769  8263|   |cb  |
+	 * |r|   | 5743 4096     0|   |cr|
+	 * |g| = |-2925 4096 -1410| x |y |
+	 * |b|   |    0 4096  7258|   |cb|
 	 *
-	 * Cb and Cr apparently come in as signed already, so no
-	 * need for any offset. For Y we need to remove the offset.
+	 * Cb and Cr apparently come in as signed already,
+	 * and we get full range data in on account of CLRC0/1
 	 */
-	I915_WRITE(SPCSCYGOFF(plane), SPCSC_OOFF(0) | SPCSC_IOFF(-64));
+	I915_WRITE(SPCSCYGOFF(plane), SPCSC_OOFF(0) | SPCSC_IOFF(0));
 	I915_WRITE(SPCSCCBOFF(plane), SPCSC_OOFF(0) | SPCSC_IOFF(0));
 	I915_WRITE(SPCSCCROFF(plane), SPCSC_OOFF(0) | SPCSC_IOFF(0));
 
-	I915_WRITE(SPCSCC01(plane), SPCSC_C1(4769) | SPCSC_C0(6537));
-	I915_WRITE(SPCSCC23(plane), SPCSC_C1(-3330) | SPCSC_C0(0));
-	I915_WRITE(SPCSCC45(plane), SPCSC_C1(-1605) | SPCSC_C0(4769));
-	I915_WRITE(SPCSCC67(plane), SPCSC_C1(4769) | SPCSC_C0(0));
-	I915_WRITE(SPCSCC8(plane), SPCSC_C0(8263));
+	I915_WRITE(SPCSCC01(plane), SPCSC_C1(4096) | SPCSC_C0(5743));
+	I915_WRITE(SPCSCC23(plane), SPCSC_C1(-2925) | SPCSC_C0(0));
+	I915_WRITE(SPCSCC45(plane), SPCSC_C1(-1410) | SPCSC_C0(4096));
+	I915_WRITE(SPCSCC67(plane), SPCSC_C1(4096) | SPCSC_C0(0));
+	I915_WRITE(SPCSCC8(plane), SPCSC_C0(7258));
 
-	I915_WRITE(SPCSCYGICLAMP(plane), SPCSC_IMAX(940) | SPCSC_IMIN(64));
-	I915_WRITE(SPCSCCBICLAMP(plane), SPCSC_IMAX(448) | SPCSC_IMIN(-448));
-	I915_WRITE(SPCSCCRICLAMP(plane), SPCSC_IMAX(448) | SPCSC_IMIN(-448));
+	I915_WRITE(SPCSCYGICLAMP(plane), SPCSC_IMAX(1023) | SPCSC_IMIN(0));
+	I915_WRITE(SPCSCCBICLAMP(plane), SPCSC_IMAX(512) | SPCSC_IMIN(-512));
+	I915_WRITE(SPCSCCRICLAMP(plane), SPCSC_IMAX(512) | SPCSC_IMIN(-512));
 
 	I915_WRITE(SPCSCYGOCLAMP(plane), SPCSC_OMAX(1023) | SPCSC_OMIN(0));
 	I915_WRITE(SPCSCCBOCLAMP(plane), SPCSC_OMAX(1023) | SPCSC_OMIN(0));
@@ -354,6 +354,36 @@ chv_update_csc(struct intel_plane *intel_plane, uint32_t format)
 }
 
 static void
+vlv_update_clrc(struct intel_plane *intel_plane, uint32_t format)
+{
+	struct drm_i915_private *dev_priv = to_i915(intel_plane->base.dev);
+	enum pipe pipe = intel_plane->pipe;
+	int plane = intel_plane->plane;
+	int con, bri, sh_sin, sh_cos;
+
+	if (format_is_yuv(format)) {
+		/*
+		 * expand limited range to full range.
+		 * contrast is applied first, then brightness
+		 */
+		con = ((255 << 7) / 219 + 1) >> 1;
+		bri = -((16 << 1) * 255 / 219 + 1) >> 1;
+		sh_sin = 0;
+		sh_cos = (((128 << 8) / 112) + 1) >> 1;
+	} else {
+		/* pass-through everything */
+		con = 1 << 6;
+		bri = 0;
+		sh_sin = 0;
+		sh_cos = 1 << 7;
+	}
+
+	/* FIXME these register are single buffered :( */
+	I915_WRITE(SPCLRC0(pipe, plane), SP_CONTRAST(con) | SP_BRIGHTNESS(bri));
+	I915_WRITE(SPCLRC1(pipe, plane), SP_SH_SIN(sh_sin) | SP_SH_COS(sh_cos));
+}
+
+static void
 vlv_update_plane(struct drm_plane *dplane,
 		 const struct intel_crtc_state *crtc_state,
 		 const struct intel_plane_state *plane_state)
@@ -461,6 +491,8 @@ vlv_update_plane(struct drm_plane *dplane,
 	if (key->flags & I915_SET_COLORKEY_SOURCE)
 		sprctl |= SP_SOURCE_KEY;
 
+	vlv_update_clrc(intel_plane, fb->pixel_format);
+
 	if (IS_CHERRYVIEW(dev) && pipe == PIPE_B)
 		chv_update_csc(intel_plane, fb->pixel_format);
 
-- 
2.7.4


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