[Intel-gfx] [PATCH v2 1/5] drm/i915: Correctly handle limited range YCbCr data on VLV/CHV

Sharma, Shashank shashank.sharma at intel.com
Thu Jun 15 12:38:43 UTC 2017


Regards

Shashank


On 6/9/2017 2:03 AM, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at 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.
>
> v2: Rebase
>
> Cc: Jyri Sarha <jsarha at ti.com>
> Cc: "Tang, Jun" <jun.tang at intel.com>
> Reported-by: "Tang, Jun" <jun.tang at intel.com>
> Cc: stable at vger.kernel.org
> Fixes: 7f1f3851feb0 ("drm/i915: sprite support for ValleyView v4")
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>   drivers/gpu/drm/i915/i915_reg.h     | 10 +++++
>   drivers/gpu/drm/i915/intel_sprite.c | 74 ++++++++++++++++++++++++++++---------
>   2 files changed, 66 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index b6d69e289974..ce7c0dc79cf7 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -5777,6 +5777,12 @@ 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)
> @@ -5790,6 +5796,8 @@ 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 _MMIO_VLV_SPR(pipe, plane_id, reg_a, reg_b) \
> @@ -5806,6 +5814,8 @@ enum {
>   #define SPKEYMAXVAL(pipe, plane_id)	_MMIO_VLV_SPR((pipe), (plane_id), _SPAKEYMAXVAL, _SPBKEYMAXVAL)
>   #define SPTILEOFF(pipe, plane_id)	_MMIO_VLV_SPR((pipe), (plane_id), _SPATILEOFF, _SPBTILEOFF)
>   #define SPCONSTALPHA(pipe, plane_id)	_MMIO_VLV_SPR((pipe), (plane_id), _SPACONSTALPHA, _SPBCONSTALPHA)
> +#define SPCLRC0(pipe, plane_id)		_MMIO_VLV_SPR((pipe), (plane_id), _SPACLRC0, _SPBCLRC0)
> +#define SPCLRC1(pipe, plane_id)		_MMIO_VLV_SPR((pipe), (plane_id), _SPACLRC1, _SPBCLRC1)
>   #define SPGAMC(pipe, plane_id)		_MMIO_VLV_SPR((pipe), (plane_id), _SPAGAMC, _SPBGAMC)
>   
>   /*
> diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
> index 0c650c2cbca8..2ce3b3c6ffa8 100644
> --- a/drivers/gpu/drm/i915/intel_sprite.c
> +++ b/drivers/gpu/drm/i915/intel_sprite.c
> @@ -325,44 +325,80 @@ skl_disable_plane(struct intel_plane *plane, struct intel_crtc *crtc)
>   }
>   
>   static void
> -chv_update_csc(struct intel_plane *plane, uint32_t format)
> +chv_update_csc(const struct intel_plane_state *plane_state)
>   {
> +	struct intel_plane *plane = to_intel_plane(plane_state->base.plane);
>   	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
> +	const struct drm_framebuffer *fb = plane_state->base.fb;
>   	enum plane_id plane_id = plane->id;
>   
>   	/* Seems RGB data bypasses the CSC always */
> -	if (!format_is_yuv(format))
> +	if (!format_is_yuv(fb->format->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_FW(SPCSCYGOFF(plane_id), SPCSC_OOFF(0) | SPCSC_IOFF(-64));
> +	I915_WRITE_FW(SPCSCYGOFF(plane_id), SPCSC_OOFF(0) | SPCSC_IOFF(0));
>   	I915_WRITE_FW(SPCSCCBOFF(plane_id), SPCSC_OOFF(0) | SPCSC_IOFF(0));
>   	I915_WRITE_FW(SPCSCCROFF(plane_id), SPCSC_OOFF(0) | SPCSC_IOFF(0));
>   
> -	I915_WRITE_FW(SPCSCC01(plane_id), SPCSC_C1(4769) | SPCSC_C0(6537));
> -	I915_WRITE_FW(SPCSCC23(plane_id), SPCSC_C1(-3330) | SPCSC_C0(0));
> -	I915_WRITE_FW(SPCSCC45(plane_id), SPCSC_C1(-1605) | SPCSC_C0(4769));
> -	I915_WRITE_FW(SPCSCC67(plane_id), SPCSC_C1(4769) | SPCSC_C0(0));
> -	I915_WRITE_FW(SPCSCC8(plane_id), SPCSC_C0(8263));
> +	I915_WRITE_FW(SPCSCC01(plane_id), SPCSC_C1(4096) | SPCSC_C0(5743));
> +	I915_WRITE_FW(SPCSCC23(plane_id), SPCSC_C1(-2925) | SPCSC_C0(0));
> +	I915_WRITE_FW(SPCSCC45(plane_id), SPCSC_C1(-1410) | SPCSC_C0(4096));
> +	I915_WRITE_FW(SPCSCC67(plane_id), SPCSC_C1(4096) | SPCSC_C0(0));
> +	I915_WRITE_FW(SPCSCC8(plane_id), SPCSC_C0(7258));
>   
> -	I915_WRITE_FW(SPCSCYGICLAMP(plane_id), SPCSC_IMAX(940) | SPCSC_IMIN(64));
> -	I915_WRITE_FW(SPCSCCBICLAMP(plane_id), SPCSC_IMAX(448) | SPCSC_IMIN(-448));
> -	I915_WRITE_FW(SPCSCCRICLAMP(plane_id), SPCSC_IMAX(448) | SPCSC_IMIN(-448));
> +	I915_WRITE_FW(SPCSCYGICLAMP(plane_id), SPCSC_IMAX(1023) | SPCSC_IMIN(0));
> +	I915_WRITE_FW(SPCSCCBICLAMP(plane_id), SPCSC_IMAX(512) | SPCSC_IMIN(-512));
> +	I915_WRITE_FW(SPCSCCRICLAMP(plane_id), SPCSC_IMAX(512) | SPCSC_IMIN(-512));
>   
>   	I915_WRITE_FW(SPCSCYGOCLAMP(plane_id), SPCSC_OMAX(1023) | SPCSC_OMIN(0));
>   	I915_WRITE_FW(SPCSCCBOCLAMP(plane_id), SPCSC_OMAX(1023) | SPCSC_OMIN(0));
>   	I915_WRITE_FW(SPCSCCROCLAMP(plane_id), SPCSC_OMAX(1023) | SPCSC_OMIN(0));
>   }
>   
> +static void
> +vlv_update_clrc(const struct intel_plane_state *plane_state)
> +{
> +	struct intel_plane *plane = to_intel_plane(plane_state->base.plane);
> +	struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
> +	const struct drm_framebuffer *fb = plane_state->base.fb;
> +	enum pipe pipe = plane->pipe;
> +	enum plane_id plane_id = plane->id;
> +	int con, bri, sh_sin, sh_cos;
> +
con = contrast bri = brightness for better reading ?
> +	if (format_is_yuv(fb->format->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;
> +	}
contrast and brightness are mostly used for color / display correction. 
Would it be better to create a
plane level property for the same, and attach into color management 
framework ? In this way, userspace
can also play around.

- Shashank
> +
> +	/* FIXME these register are single buffered :( */
> +	I915_WRITE_FW(SPCLRC0(pipe, plane_id),
> +		      SP_CONTRAST(con) | SP_BRIGHTNESS(bri));
> +	I915_WRITE_FW(SPCLRC1(pipe, plane_id),
> +		      SP_SH_SIN(sh_sin) | SP_SH_COS(sh_cos));
> +}
> +
>   static u32 vlv_sprite_ctl(const struct intel_crtc_state *crtc_state,
>   			  const struct intel_plane_state *plane_state)
>   {
> @@ -456,8 +492,10 @@ vlv_update_plane(struct intel_plane *plane,
>   
>   	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
>   
> +	vlv_update_clrc(plane_state);
> +
>   	if (IS_CHERRYVIEW(dev_priv) && pipe == PIPE_B)
> -		chv_update_csc(plane, fb->format->format);
> +		chv_update_csc(plane_state);
>   
>   	if (key->flags) {
>   		I915_WRITE_FW(SPKEYMINVAL(pipe, plane_id), key->min_value);



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