Re: [PATCH] drm/core: Change declaration for gamma_set.

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Jun 06, 2016 at 11:18:09AM +0200, Maarten Lankhorst wrote:
> Change return value to int to propagate errors from gamma_set,
> and remove start parameter. Updates always use the full size,
> and some drivers even ignore the start parameter altogether.

Commit message should explain why we suddenly need to pass up the error
code, too:

"This is needed for atomic drivers, where an atomic commit can fail with
EAGAIN and should be restarted."

I'll add that when merging, but will wait for a bit more acks/r-b first.
-Daniel
> 
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Christian König <christian.koenig@amd.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
> Cc: Ben Skeggs <bskeggs@redhat.com>
> Cc: Eric Anholt <eric@anholt.net>
> Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
> Cc: Mathieu Larouche <mathieu.larouche@matrox.com>
> Cc: Thierry Reding <treding@nvidia.com>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/dce_v10_0.c  | 10 ++++++----
>  drivers/gpu/drm/amd/amdgpu/dce_v11_0.c  | 10 ++++++----
>  drivers/gpu/drm/amd/amdgpu/dce_v8_0.c   | 10 ++++++----
>  drivers/gpu/drm/ast/ast_mode.c          | 10 ++++++----
>  drivers/gpu/drm/cirrus/cirrus_mode.c    |  8 +++++---
>  drivers/gpu/drm/drm_atomic_helper.c     | 13 ++++++-------
>  drivers/gpu/drm/drm_crtc.c              |  2 +-
>  drivers/gpu/drm/drm_fb_helper.c         |  4 +---
>  drivers/gpu/drm/gma500/gma_display.c    |  9 +++++----
>  drivers/gpu/drm/gma500/gma_display.h    |  4 ++--
>  drivers/gpu/drm/mgag200/mgag200_mode.c  |  9 +++++----
>  drivers/gpu/drm/nouveau/dispnv04/crtc.c | 12 +++++++-----
>  drivers/gpu/drm/nouveau/nv50_display.c  |  9 +++++----
>  drivers/gpu/drm/radeon/radeon_display.c | 11 +++++++----
>  drivers/gpu/drm/vc4/vc4_crtc.c          |  8 +++++---
>  drivers/gpu/drm/vmwgfx/vmwgfx_kms.c     |  8 +++++---
>  drivers/gpu/drm/vmwgfx/vmwgfx_kms.h     |  4 ++--
>  include/drm/drm_atomic_helper.h         |  6 +++---
>  include/drm/drm_crtc.h                  |  4 ++--
>  19 files changed, 85 insertions(+), 66 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> index 8227344d2ff6..16de862ea51f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v10_0.c
> @@ -2667,19 +2667,21 @@ static void dce_v10_0_cursor_reset(struct drm_crtc *crtc)
>  	}
>  }
>  
> -static void dce_v10_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> -				    u16 *blue, uint32_t start, uint32_t size)
> +static int dce_v10_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> +				    u16 *blue, uint32_t size)
>  {
>  	struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
> -	int end = (start + size > 256) ? 256 : start + size, i;
> +	int i;
>  
>  	/* userspace palettes are always correct as is */
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		amdgpu_crtc->lut_r[i] = red[i] >> 6;
>  		amdgpu_crtc->lut_g[i] = green[i] >> 6;
>  		amdgpu_crtc->lut_b[i] = blue[i] >> 6;
>  	}
>  	dce_v10_0_crtc_load_lut(crtc);
> +
> +	return 0;
>  }
>  
>  static void dce_v10_0_crtc_destroy(struct drm_crtc *crtc)
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> index af26ec0bc59d..6e0ae8e2e65c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v11_0.c
> @@ -2678,19 +2678,21 @@ static void dce_v11_0_cursor_reset(struct drm_crtc *crtc)
>  	}
>  }
>  
> -static void dce_v11_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> -				    u16 *blue, uint32_t start, uint32_t size)
> +static int dce_v11_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> +				    u16 *blue, uint32_t size)
>  {
>  	struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
> -	int end = (start + size > 256) ? 256 : start + size, i;
> +	int i;
>  
>  	/* userspace palettes are always correct as is */
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		amdgpu_crtc->lut_r[i] = red[i] >> 6;
>  		amdgpu_crtc->lut_g[i] = green[i] >> 6;
>  		amdgpu_crtc->lut_b[i] = blue[i] >> 6;
>  	}
>  	dce_v11_0_crtc_load_lut(crtc);
> +
> +	return 0;
>  }
>  
>  static void dce_v11_0_crtc_destroy(struct drm_crtc *crtc)
> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> index 3fb65e41a6ef..7b5fae4c74f1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_v8_0.c
> @@ -2574,19 +2574,21 @@ static void dce_v8_0_cursor_reset(struct drm_crtc *crtc)
>  	}
>  }
>  
> -static void dce_v8_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> -				    u16 *blue, uint32_t start, uint32_t size)
> +static int dce_v8_0_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> +				   u16 *blue, uint32_t size)
>  {
>  	struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
> -	int end = (start + size > 256) ? 256 : start + size, i;
> +	int i;
>  
>  	/* userspace palettes are always correct as is */
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		amdgpu_crtc->lut_r[i] = red[i] >> 6;
>  		amdgpu_crtc->lut_g[i] = green[i] >> 6;
>  		amdgpu_crtc->lut_b[i] = blue[i] >> 6;
>  	}
>  	dce_v8_0_crtc_load_lut(crtc);
> +
> +	return 0;
>  }
>  
>  static void dce_v8_0_crtc_destroy(struct drm_crtc *crtc)
> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
> index c337922606e3..5957c3e659fe 100644
> --- a/drivers/gpu/drm/ast/ast_mode.c
> +++ b/drivers/gpu/drm/ast/ast_mode.c
> @@ -624,19 +624,21 @@ static void ast_crtc_reset(struct drm_crtc *crtc)
>  
>  }
>  
> -static void ast_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> -				 u16 *blue, uint32_t start, uint32_t size)
> +static int ast_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> +			      u16 *blue, uint32_t size)
>  {
>  	struct ast_crtc *ast_crtc = to_ast_crtc(crtc);
> -	int end = (start + size > 256) ? 256 : start + size, i;
> +	int i;
>  
>  	/* userspace palettes are always correct as is */
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		ast_crtc->lut_r[i] = red[i] >> 8;
>  		ast_crtc->lut_g[i] = green[i] >> 8;
>  		ast_crtc->lut_b[i] = blue[i] >> 8;
>  	}
>  	ast_crtc_load_lut(crtc);
> +
> +	return 0;
>  }
>  
>  
> diff --git a/drivers/gpu/drm/cirrus/cirrus_mode.c b/drivers/gpu/drm/cirrus/cirrus_mode.c
> index 0b1a411cb89e..17c915d9a03e 100644
> --- a/drivers/gpu/drm/cirrus/cirrus_mode.c
> +++ b/drivers/gpu/drm/cirrus/cirrus_mode.c
> @@ -325,18 +325,20 @@ static void cirrus_crtc_commit(struct drm_crtc *crtc)
>   * use this for 8-bit mode so can't perform smooth fades on deeper modes,
>   * but it's a requirement that we provide the function
>   */
> -static void cirrus_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> -				  u16 *blue, uint32_t start, uint32_t size)
> +static int cirrus_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> +				 u16 *blue, uint32_t size)
>  {
>  	struct cirrus_crtc *cirrus_crtc = to_cirrus_crtc(crtc);
>  	int i;
>  
> -	for (i = 0; i < CIRRUS_LUT_SIZE; i++) {
> +	for (i = 0; i < size; i++) {
>  		cirrus_crtc->lut_r[i] = red[i];
>  		cirrus_crtc->lut_g[i] = green[i];
>  		cirrus_crtc->lut_b[i] = blue[i];
>  	}
>  	cirrus_crtc_load_lut(crtc);
> +
> +	return 0;
>  }
>  
>  /* Simple cleanup function */
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 939df900dcaa..266c11018a19 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -2933,16 +2933,15 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_destroy_state);
>   * @red: red correction table
>   * @green: green correction table
>   * @blue: green correction table
> - * @start:
>   * @size: size of the tables
>   *
>   * Implements support for legacy gamma correction table for drivers
>   * that support color management through the DEGAMMA_LUT/GAMMA_LUT
>   * properties.
>   */
> -void drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> -					u16 *red, u16 *green, u16 *blue,
> -					uint32_t start, uint32_t size)
> +int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> +				       u16 *red, u16 *green, u16 *blue,
> +				       uint32_t size)
>  {
>  	struct drm_device *dev = crtc->dev;
>  	struct drm_mode_config *config = &dev->mode_config;
> @@ -2954,7 +2953,7 @@ void drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
>  
>  	state = drm_atomic_state_alloc(crtc->dev);
>  	if (!state)
> -		return;
> +		return -ENOMEM;
>  
>  	blob = drm_property_create_blob(dev,
>  					sizeof(struct drm_color_lut) * size,
> @@ -3005,7 +3004,7 @@ retry:
>  
>  	drm_property_unreference_blob(blob);
>  
> -	return;
> +	return 0;
>  fail:
>  	if (ret == -EDEADLK)
>  		goto backoff;
> @@ -3013,7 +3012,7 @@ fail:
>  	drm_atomic_state_free(state);
>  	drm_property_unreference_blob(blob);
>  
> -	return;
> +	return ret;
>  backoff:
>  	drm_atomic_state_clear(state);
>  	drm_atomic_legacy_backoff(state);
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index d2a6d958ca76..4d61ceae789c 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -5215,7 +5215,7 @@ int drm_mode_gamma_set_ioctl(struct drm_device *dev,
>  		goto out;
>  	}
>  
> -	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size);
> +	ret = crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, crtc->gamma_size);
>  
>  out:
>  	drm_modeset_unlock_all(dev);
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 7590df5e2e72..4accf6039058 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -227,7 +227,7 @@ static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
>  	g_base = r_base + crtc->gamma_size;
>  	b_base = g_base + crtc->gamma_size;
>  
> -	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size);
> +	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, crtc->gamma_size);
>  }
>  
>  /**
> @@ -1076,8 +1076,6 @@ static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
>  	WARN_ON(fb->bits_per_pixel != 8);
>  
>  	fb_helper->funcs->gamma_set(crtc, red, green, blue, regno);
> -
> -	return 0;
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/gma500/gma_display.c b/drivers/gpu/drm/gma500/gma_display.c
> index c95406e6f44d..5b636bf0b467 100644
> --- a/drivers/gpu/drm/gma500/gma_display.c
> +++ b/drivers/gpu/drm/gma500/gma_display.c
> @@ -175,20 +175,21 @@ void gma_crtc_load_lut(struct drm_crtc *crtc)
>  	}
>  }
>  
> -void gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green, u16 *blue,
> -			u32 start, u32 size)
> +int gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green, u16 *blue,
> +		       u32 size)
>  {
>  	struct gma_crtc *gma_crtc = to_gma_crtc(crtc);
>  	int i;
> -	int end = (start + size > 256) ? 256 : start + size;
>  
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		gma_crtc->lut_r[i] = red[i] >> 8;
>  		gma_crtc->lut_g[i] = green[i] >> 8;
>  		gma_crtc->lut_b[i] = blue[i] >> 8;
>  	}
>  
>  	gma_crtc_load_lut(crtc);
> +
> +	return 0;
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/gma500/gma_display.h b/drivers/gpu/drm/gma500/gma_display.h
> index b2491c65f053..e72dd08b701b 100644
> --- a/drivers/gpu/drm/gma500/gma_display.h
> +++ b/drivers/gpu/drm/gma500/gma_display.h
> @@ -72,8 +72,8 @@ extern int gma_crtc_cursor_set(struct drm_crtc *crtc,
>  			       uint32_t width, uint32_t height);
>  extern int gma_crtc_cursor_move(struct drm_crtc *crtc, int x, int y);
>  extern void gma_crtc_load_lut(struct drm_crtc *crtc);
> -extern void gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> -			       u16 *blue, u32 start, u32 size);
> +extern int gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> +			      u16 *blue, u32 size);
>  extern void gma_crtc_dpms(struct drm_crtc *crtc, int mode);
>  extern void gma_crtc_prepare(struct drm_crtc *crtc);
>  extern void gma_crtc_commit(struct drm_crtc *crtc);
> diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
> index 14e64e08909e..f6d5892d03f1 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_mode.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
> @@ -1344,19 +1344,20 @@ static void mga_crtc_commit(struct drm_crtc *crtc)
>   * use this for 8-bit mode so can't perform smooth fades on deeper modes,
>   * but it's a requirement that we provide the function
>   */
> -static void mga_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> -				  u16 *blue, uint32_t start, uint32_t size)
> +static int mga_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> +			      u16 *blue, uint32_t size)
>  {
>  	struct mga_crtc *mga_crtc = to_mga_crtc(crtc);
> -	int end = (start + size > MGAG200_LUT_SIZE) ? MGAG200_LUT_SIZE : start + size;
>  	int i;
>  
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		mga_crtc->lut_r[i] = red[i] >> 8;
>  		mga_crtc->lut_g[i] = green[i] >> 8;
>  		mga_crtc->lut_b[i] = blue[i] >> 8;
>  	}
>  	mga_crtc_load_lut(crtc);
> +
> +	return 0;
>  }
>  
>  /* Simple cleanup function */
> diff --git a/drivers/gpu/drm/nouveau/dispnv04/crtc.c b/drivers/gpu/drm/nouveau/dispnv04/crtc.c
> index 6f318c54da33..0cb7a18cde26 100644
> --- a/drivers/gpu/drm/nouveau/dispnv04/crtc.c
> +++ b/drivers/gpu/drm/nouveau/dispnv04/crtc.c
> @@ -785,14 +785,14 @@ nv_crtc_disable(struct drm_crtc *crtc)
>  	nouveau_bo_ref(NULL, &disp->image[nv_crtc->index]);
>  }
>  
> -static void
> -nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, uint32_t start,
> +static int
> +nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
>  		  uint32_t size)
>  {
> -	int end = (start + size > 256) ? 256 : start + size, i;
>  	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
> +	int i;
>  
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		nv_crtc->lut.r[i] = r[i];
>  		nv_crtc->lut.g[i] = g[i];
>  		nv_crtc->lut.b[i] = b[i];
> @@ -805,10 +805,12 @@ nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, uint32_t start,
>  	 */
>  	if (!nv_crtc->base.primary->fb) {
>  		nv_crtc->lut.depth = 0;
> -		return;
> +		return 0;
>  	}
>  
>  	nv_crtc_gamma_load(crtc);
> +
> +	return 0;
>  }
>  
>  static int
> diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
> index 3ffc2b0057bf..7a7788212df7 100644
> --- a/drivers/gpu/drm/nouveau/nv50_display.c
> +++ b/drivers/gpu/drm/nouveau/nv50_display.c
> @@ -1346,21 +1346,22 @@ nv50_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
>  	return 0;
>  }
>  
> -static void
> +static int
>  nv50_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
> -		    uint32_t start, uint32_t size)
> +		    uint32_t size)
>  {
>  	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
> -	u32 end = min_t(u32, start + size, 256);
>  	u32 i;
>  
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		nv_crtc->lut.r[i] = r[i];
>  		nv_crtc->lut.g[i] = g[i];
>  		nv_crtc->lut.b[i] = b[i];
>  	}
>  
>  	nv50_crtc_lut_load(crtc);
> +
> +	return 0;
>  }
>  
>  static void
> diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
> index 6a41b4982647..80f06db1dd34 100644
> --- a/drivers/gpu/drm/radeon/radeon_display.c
> +++ b/drivers/gpu/drm/radeon/radeon_display.c
> @@ -231,19 +231,21 @@ void radeon_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
>  	*blue = radeon_crtc->lut_b[regno] << 6;
>  }
>  
> -static void radeon_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> -				  u16 *blue, uint32_t start, uint32_t size)
> +static int radeon_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
> +				 u16 *blue, uint32_t size)
>  {
>  	struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
> -	int end = (start + size > 256) ? 256 : start + size, i;
> +	int i;
>  
>  	/* userspace palettes are always correct as is */
> -	for (i = start; i < end; i++) {
> +	for (i = 0; i < size; i++) {
>  		radeon_crtc->lut_r[i] = red[i] >> 6;
>  		radeon_crtc->lut_g[i] = green[i] >> 6;
>  		radeon_crtc->lut_b[i] = blue[i] >> 6;
>  	}
>  	radeon_crtc_load_lut(crtc);
> +
> +	return 0;
>  }
>  
>  static void radeon_crtc_destroy(struct drm_crtc *crtc)
> @@ -688,6 +690,7 @@ radeon_crtc_set_config(struct drm_mode_set *set)
>  	pm_runtime_put_autosuspend(dev->dev);
>  	return ret;
>  }
> +
>  static const struct drm_crtc_funcs radeon_crtc_funcs = {
>  	.cursor_set2 = radeon_crtc_cursor_set2,
>  	.cursor_move = radeon_crtc_cursor_move,
> diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
> index 904d0754ad78..4e34f054da5c 100644
> --- a/drivers/gpu/drm/vc4/vc4_crtc.c
> +++ b/drivers/gpu/drm/vc4/vc4_crtc.c
> @@ -175,20 +175,22 @@ vc4_crtc_lut_load(struct drm_crtc *crtc)
>  		HVS_WRITE(SCALER_GAMDATA, vc4_crtc->lut_b[i]);
>  }
>  
> -static void
> +static int
>  vc4_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
> -		   uint32_t start, uint32_t size)
> +		   uint32_t size)
>  {
>  	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
>  	u32 i;
>  
> -	for (i = start; i < start + size; i++) {
> +	for (i = 0; i < size; i++) {
>  		vc4_crtc->lut_r[i] = r[i] >> 8;
>  		vc4_crtc->lut_g[i] = g[i] >> 8;
>  		vc4_crtc->lut_b[i] = b[i] >> 8;
>  	}
>  
>  	vc4_crtc_lut_load(crtc);
> +
> +	return 0;
>  }
>  
>  static u32 vc4_get_fifo_full_level(u32 format)
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
> index 55231cce73a0..8a69d4da40b5 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
> @@ -1404,9 +1404,9 @@ static int vmw_du_update_layout(struct vmw_private *dev_priv, unsigned num,
>  	return 0;
>  }
>  
> -void vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
> -			   u16 *r, u16 *g, u16 *b,
> -			   uint32_t start, uint32_t size)
> +int vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
> +			  u16 *r, u16 *g, u16 *b,
> +			  uint32_t size)
>  {
>  	struct vmw_private *dev_priv = vmw_priv(crtc->dev);
>  	int i;
> @@ -1418,6 +1418,8 @@ void vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
>  		vmw_write(dev_priv, SVGA_PALETTE_BASE + i * 3 + 1, g[i] >> 8);
>  		vmw_write(dev_priv, SVGA_PALETTE_BASE + i * 3 + 2, b[i] >> 8);
>  	}
> +
> +	return 0;
>  }
>  
>  int vmw_du_connector_dpms(struct drm_connector *connector, int mode)
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
> index 57203212c501..ff4803c107bc 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.h
> @@ -195,9 +195,9 @@ struct vmw_display_unit {
>  void vmw_du_cleanup(struct vmw_display_unit *du);
>  void vmw_du_crtc_save(struct drm_crtc *crtc);
>  void vmw_du_crtc_restore(struct drm_crtc *crtc);
> -void vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
> +int vmw_du_crtc_gamma_set(struct drm_crtc *crtc,
>  			   u16 *r, u16 *g, u16 *b,
> -			   uint32_t start, uint32_t size);
> +			   uint32_t size);
>  int vmw_du_crtc_cursor_set2(struct drm_crtc *crtc, struct drm_file *file_priv,
>  			    uint32_t handle, uint32_t width, uint32_t height,
>  			    int32_t hot_x, int32_t hot_y);
> diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> index d473dcc91f54..11896c84c4f8 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -147,9 +147,9 @@ void
>  __drm_atomic_helper_connector_destroy_state(struct drm_connector_state *state);
>  void drm_atomic_helper_connector_destroy_state(struct drm_connector *connector,
>  					  struct drm_connector_state *state);
> -void drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> -					u16 *red, u16 *green, u16 *blue,
> -					uint32_t start, uint32_t size);
> +int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
> +				       u16 *red, u16 *green, u16 *blue,
> +				       uint32_t size);
>  
>  /**
>   * drm_atomic_crtc_for_each_plane - iterate over planes currently attached to CRTC
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index d1559cd04e3d..8622bb2f4f25 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -478,8 +478,8 @@ struct drm_crtc_funcs {
>  	 * going on, which should eventually be unified to just one set of
>  	 * hooks.
>  	 */
> -	void (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
> -			  uint32_t start, uint32_t size);
> +	int (*gamma_set)(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
> +			 uint32_t size);
>  
>  	/**
>  	 * @destroy:
> -- 
> 2.5.5
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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