On Mon, Oct 19, 2015 at 06:08:52PM +0000, Smith, Gary K wrote:
> FYI - this shouldn't block the commits, but should be optimized later (fairly soon).
>
> I believe the current implementation ends up executing
> while (count < CHV_DEGAMMA_MAX_VALS) {
> // Do lots of caclulation
> I915_WRITE(cgm_degamma_reg, word);
> Every frame after you set the property, whether you change the contents of the blob or not. Clearly this is really inefficient when there are 100s of gamma values to write.
> Same with the Gamma and CTM. CTM is less of an issue with only 9 entries.
>
> My suggestion here is to set a boolean when the property has been set as
> part of a flip and only apply it on the atomic commit after the update
> was received.
Yeah the usual design is to add a foo_changed boolean (or bitmask, e.g.
for changed planes tracked in the crtc_state) in the state where we need
to commit the update. That /should/ be there really, didn't ever realize
it's not done. Note that that for legacy cursors we update them without
waiting for vblanks and legacy userspace does that a _lot_ (*cough* X
server *cough*), if the overhead is severe this might be a problem and
needs to be fixed before merging.
-Daniel
>
> Thanks
> Gary
>
> -----Original Message-----
> From: Sharma, Shashank
> Sent: Friday, October 16, 2015 3:29 PM
> To: dri-devel@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; emil.l.velikov@xxxxxxxxx; Roper, Matthew D; Bradford, Robert; Bish, Jim
> Cc: Matheson, Annie J; kausalmalladi@xxxxxxxxx; Kumar, Kiran S; Smith, Gary K; Vetter, Daniel; Mukherjee, Indranil; Palleti, Avinash Reddy; Sharma, Shashank
> Subject: [PATCH v6 14/23] drm/i915: CHV: Pipe level degamma correction
>
> CHV/BSW supports Degamma color correction, which linearizes all the non-linear color values. This will be applied before Color Transformation.
>
> This patch does the following:
> 1. Attach deGamma property to CRTC
> 2. Add the core function to program DeGamma correction values for
> CHV/BSW platform
> 2. Add DeGamma correction macros/defines
>
> Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxxxx>
> Signed-off-by: Kausal Malladi <kausalmalladi@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 6 ++
> drivers/gpu/drm/i915/intel_color_manager.c | 92 ++++++++++++++++++++++++++++++ drivers/gpu/drm/i915/intel_color_manager.h | 5 ++
> 3 files changed, 103 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 45ddd84..1e46562 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -8160,4 +8160,10 @@ enum skl_disp_power_wells { #define _PIPE_GAMMA_BASE(pipe) \
> (_PIPE3(pipe, PIPEA_CGM_GAMMA, PIPEB_CGM_GAMMA, PIPEC_CGM_GAMMA))
>
> +#define PIPEA_CGM_DEGAMMA (VLV_DISPLAY_BASE + 0x66000)
> +#define PIPEB_CGM_DEGAMMA (VLV_DISPLAY_BASE + 0x68000)
> +#define PIPEC_CGM_DEGAMMA (VLV_DISPLAY_BASE + 0x6A000)
> +#define _PIPE_DEGAMMA_BASE(pipe) \
> + (_PIPE3(pipe, PIPEA_CGM_DEGAMMA, PIPEB_CGM_DEGAMMA,
> +PIPEC_CGM_DEGAMMA))
> +
> #endif /* _I915_REG_H_ */
> diff --git a/drivers/gpu/drm/i915/intel_color_manager.c b/drivers/gpu/drm/i915/intel_color_manager.c
> index acb9647..1bbad79 100644
> --- a/drivers/gpu/drm/i915/intel_color_manager.c
> +++ b/drivers/gpu/drm/i915/intel_color_manager.c
> @@ -27,6 +27,92 @@
>
> #include "intel_color_manager.h"
>
> +static int chv_set_degamma(struct drm_device *dev,
> + struct drm_property_blob *blob, struct drm_crtc *crtc) {
> + u16 red_fract, green_fract, blue_fract;
> + u32 red, green, blue;
> + u32 num_samples;
> + u32 word = 0;
> + u32 count, cgm_control_reg, cgm_degamma_reg;
> + enum pipe pipe;
> + struct drm_palette *degamma_data;
> + struct drm_i915_private *dev_priv = dev->dev_private;
> + struct drm_r32g32b32 *correction_values = NULL;
> + struct drm_crtc_state *state = crtc->state;
> +
> + if (WARN_ON(!blob))
> + return -EINVAL;
> +
> + degamma_data = (struct drm_palette *)blob->data;
> + pipe = to_intel_crtc(crtc)->pipe;
> + num_samples = blob->length / sizeof(struct drm_r32g32b32);
> +
> + switch (num_samples) {
> + case GAMMA_DISABLE_VALS:
> + /* Disable DeGamma functionality on Pipe - CGM Block */
> + cgm_control_reg = I915_READ(_PIPE_CGM_CONTROL(pipe));
> + cgm_control_reg &= ~CGM_DEGAMMA_EN;
> + state->palette_before_ctm_blob = NULL;
> +
> + I915_WRITE(_PIPE_CGM_CONTROL(pipe), cgm_control_reg);
> + DRM_DEBUG_DRIVER("DeGamma disabled on Pipe %c\n",
> + pipe_name(pipe));
> + break;
> +
> + case CHV_DEGAMMA_MAX_VALS:
> + cgm_degamma_reg = _PIPE_DEGAMMA_BASE(pipe);
> + count = 0;
> + correction_values = (struct drm_r32g32b32 *)°amma_data->lut;
> + while (count < CHV_DEGAMMA_MAX_VALS) {
> + blue = correction_values[count].b32;
> + green = correction_values[count].g32;
> + red = correction_values[count].r32;
> +
> + if (blue > CHV_MAX_GAMMA)
> + blue = CHV_MAX_GAMMA;
> +
> + if (green > CHV_MAX_GAMMA)
> + green = CHV_MAX_GAMMA;
> +
> + if (red > CHV_MAX_GAMMA)
> + red = CHV_MAX_GAMMA;
> +
> + blue_fract = GET_BITS(blue, 8, 14);
> + green_fract = GET_BITS(green, 8, 14);
> + red_fract = GET_BITS(red, 8, 14);
> +
> + /* Green (29:16) and Blue (13:0) in DWORD1 */
> + SET_BITS(word, green_fract, 16, 14);
> + SET_BITS(word, green_fract, 0, 14);
> + I915_WRITE(cgm_degamma_reg, word);
> + cgm_degamma_reg += 4;
> +
> + /* Red (13:0) to be written to DWORD2 */
> + word = red_fract;
> + I915_WRITE(cgm_degamma_reg, word);
> + cgm_degamma_reg += 4;
> + count++;
> + }
> +
> + DRM_DEBUG_DRIVER("DeGamma LUT loaded for Pipe %c\n",
> + pipe_name(pipe));
> +
> + /* Enable DeGamma on Pipe */
> + I915_WRITE(_PIPE_CGM_CONTROL(pipe),
> + I915_READ(_PIPE_CGM_CONTROL(pipe)) | CGM_DEGAMMA_EN);
> +
> + DRM_DEBUG_DRIVER("DeGamma correction enabled on Pipe %c\n",
> + pipe_name(pipe));
> + break;
> +
> + default:
> + DRM_ERROR("Invalid number of samples for DeGamma LUT\n");
> + return -EINVAL;
> + }
> + return 0;
> +}
> +
> static int chv_set_gamma(struct drm_device *dev, struct drm_property_blob *blob,
> struct drm_crtc *crtc)
> {
> @@ -155,4 +241,10 @@ void intel_attach_color_properties_to_crtc(struct drm_device *dev,
> DRM_DEBUG_DRIVER("gamma property attached to CRTC\n");
> }
>
> + /* Degamma correction */
> + if (config->cm_palette_before_ctm_property) {
> + drm_object_attach_property(mode_obj,
> + config->cm_palette_before_ctm_property, 0);
> + DRM_DEBUG_DRIVER("degamma property attached to CRTC\n");
> + }
> }
> diff --git a/drivers/gpu/drm/i915/intel_color_manager.h b/drivers/gpu/drm/i915/intel_color_manager.h
> index de706d9..77a2119 100644
> --- a/drivers/gpu/drm/i915/intel_color_manager.h
> +++ b/drivers/gpu/drm/i915/intel_color_manager.h
> @@ -63,5 +63,10 @@
> #define CHV_GAMMA_SHIFT_GREEN 16
> #define CHV_MAX_GAMMA ((1 << 24) - 1)
>
> +/* Degamma on CHV */
> +#define CHV_DEGAMMA_MSB_SHIFT 2
> +#define CHV_DEGAMMA_GREEN_SHIFT 16
> +
> /* CHV CGM Block */
> #define CGM_GAMMA_EN (1 << 2)
> +#define CGM_DEGAMMA_EN (1 << 0)
> --
> 1.9.1
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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