Re: [PATCH v5 2/3] drm: Add Gamma and Degamma LUT sizes props to drm_crtc to validate.

From: Ilia Mirkin
Date: Thu Nov 04 2021 - 17:15:58 EST


On Thu, Nov 4, 2021 at 4:03 PM Mark Yacoub <markyacoub@xxxxxxxxxxxx> wrote:
>
> From: Mark Yacoub <markyacoub@xxxxxxxxxx>
>
> [Why]
> 1. drm_atomic_helper_check doesn't check for the LUT sizes of either Gamma
> or Degamma props in the new CRTC state, allowing any invalid size to
> be passed on.
> 2. Each driver has its own LUT size, which could also be different for
> legacy users.
>
> [How]
> 1. Create |degamma_lut_size| and |gamma_lut_size| to save the LUT sizes
> assigned by the driver when it's initializing its color and CTM
> management.
> 2. Create drm_atomic_helper_check_crtc which is called by
> drm_atomic_helper_check to check the LUT sizes saved in drm_crtc that
> they match the sizes in the new CRTC state.
> 3. As the LUT size check now happens in drm_atomic_helper_check, remove
> the lut check in intel_color.c
>
> Resolves: igt@kms_color@pipe-A-invalid-gamma-lut-sizes on MTK
> Tested on Zork (amdgpu) and Jacuzzi (mediatek), volteer (TGL)
>
> v3:
> 1. Check for lut pointer inside drm_check_lut_size.
>
> v2:
> 1. Remove the rename to a parent commit.
> 2. Create a drm drm_check_lut_size instead of intel only function.
>
> v1:
> 1. Fix typos
> 2. Remove the LUT size check from intel driver
> 3. Rename old LUT check to indicate it's a channel change
>
> Signed-off-by: Mark Yacoub <markyacoub@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_atomic_helper.c | 52 ++++++++++++++++++++++
> drivers/gpu/drm/drm_color_mgmt.c | 19 ++++++++
> drivers/gpu/drm/i915/display/intel_color.c | 32 ++++++-------
> include/drm/drm_atomic_helper.h | 1 +
> include/drm/drm_color_mgmt.h | 3 ++
> include/drm/drm_crtc.h | 11 +++++
> 6 files changed, 99 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index bc3487964fb5e..548e5d8221fb4 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -929,6 +929,54 @@ drm_atomic_helper_check_planes(struct drm_device *dev,
> }
> EXPORT_SYMBOL(drm_atomic_helper_check_planes);
>
> +/**
> + * drm_atomic_helper_check_crtcs - validate state object for CRTC changes
> + * @state: the driver state object
> + *
> + * Check the CRTC state object such as the Gamma/Degamma LUT sizes if the new
> + * state holds them.
> + *
> + * RETURNS:
> + * Zero for success or -errno
> + */
> +int drm_atomic_helper_check_crtcs(struct drm_atomic_state *state)
> +{
> + struct drm_crtc *crtc;
> + struct drm_crtc_state *new_crtc_state;
> + int i;
> +
> + for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
> + if (!new_crtc_state->color_mgmt_changed)
> + continue;
> +
> + if (drm_check_lut_size(new_crtc_state->gamma_lut,
> + crtc->gamma_lut_size) ||
> + drm_check_lut_size(new_crtc_state->gamma_lut,
> + crtc->gamma_size)) {
> + drm_dbg_state(
> + state->dev,
> + "Invalid Gamma LUT size. Expected %u/%u, got %u.\n",
> + crtc->gamma_lut_size, crtc->gamma_size,
> + drm_color_lut_size(new_crtc_state->gamma_lut));
> + return -EINVAL;
> + }
> +
> + if (drm_check_lut_size(new_crtc_state->degamma_lut,
> + crtc->degamma_lut_size)) {
> + drm_dbg_state(
> + state->dev,
> + "Invalid Degamma LUT size. Expected %u, got %u.\n",
> + crtc->degamma_lut_size,
> + drm_color_lut_size(
> + new_crtc_state->degamma_lut));
> + return -EINVAL;
> + }
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_check_crtcs);
> +
> /**
> * drm_atomic_helper_check - validate state object
> * @dev: DRM device
> @@ -974,6 +1022,10 @@ int drm_atomic_helper_check(struct drm_device *dev,
> if (ret)
> return ret;
>
> + ret = drm_atomic_helper_check_crtcs(state);
> + if (ret)
> + return ret;
> +
> if (state->legacy_cursor_update)
> state->async_update = !drm_atomic_helper_async_check(dev, state);
>
> diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
> index 16a07f84948f3..c85094223b535 100644
> --- a/drivers/gpu/drm/drm_color_mgmt.c
> +++ b/drivers/gpu/drm/drm_color_mgmt.c
> @@ -166,6 +166,7 @@ void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
> struct drm_mode_config *config = &dev->mode_config;
>
> if (degamma_lut_size) {
> + crtc->degamma_lut_size = degamma_lut_size;
> drm_object_attach_property(&crtc->base,
> config->degamma_lut_property, 0);
> drm_object_attach_property(&crtc->base,
> @@ -178,6 +179,7 @@ void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
> config->ctm_property, 0);
>
> if (gamma_lut_size) {
> + crtc->gamma_lut_size = gamma_lut_size;
> drm_object_attach_property(&crtc->base,
> config->gamma_lut_property, 0);
> drm_object_attach_property(&crtc->base,
> @@ -506,6 +508,23 @@ const char *drm_get_color_range_name(enum drm_color_range range)
> return color_range_name[range];
> }
>
> +/**
> + * drm_check_lut_size - Checks if LUT size matches the driver expected size.
> + * @lut: blob containing the LUT
> + * @expected_size: driver expected LUT size
> + *
> + * Returns -EINVAL on mismatch, 0 on match.
> + */
> +int drm_check_lut_size(const struct drm_property_blob *lut,
> + uint32_t expected_size)
> +{
> + if (!lut)
> + return 0;
> +
> + return drm_color_lut_size(lut) != expected_size ? -EINVAL : 0;
> +}
> +EXPORT_SYMBOL(drm_check_lut_size);
> +
> /**
> * drm_plane_create_color_properties - color encoding related plane properties
> * @plane: plane object
> diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
> index 1469871d21ff9..0fe4b2359812a 100644
> --- a/drivers/gpu/drm/i915/display/intel_color.c
> +++ b/drivers/gpu/drm/i915/display/intel_color.c
> @@ -1262,23 +1262,6 @@ intel_color_add_affected_planes(struct intel_crtc_state *new_crtc_state)
> return 0;
> }
>
> -static int check_lut_size(const struct drm_property_blob *lut, int expected)
> -{
> - int len;
> -
> - if (!lut)
> - return 0;
> -
> - len = drm_color_lut_size(lut);
> - if (len != expected) {
> - DRM_DEBUG_KMS("Invalid LUT size; got %d, expected %d\n",
> - len, expected);
> - return -EINVAL;
> - }
> -
> - return 0;
> -}
> -
> static int test_luts(const struct drm_property_blob *lut, u32 tests)
> {
> const struct drm_color_lut *entry;
> @@ -1336,9 +1319,20 @@ static int check_luts(const struct intel_crtc_state *crtc_state)
> degamma_channels_tests = INTEL_INFO(dev_priv)->color.degamma_lut_tests;
> gamma_channels_tests = INTEL_INFO(dev_priv)->color.gamma_lut_tests;
>
> - if (check_lut_size(degamma_lut, degamma_length) ||
> - check_lut_size(gamma_lut, gamma_length))
> + if (drm_check_lut_size(degamma_lut, degamma_length)) {
> + drm_dbg_state(
> + &dev_priv->drm,
> + "Invalid Degamma LUT size. Expected %u, got %u.\n",
> + degamma_length, drm_color_lut_size(degamma_lut));
> return -EINVAL;
> + }
> +
> + if (drm_check_lut_size(gamma_lut, gamma_length)) {
> + drm_dbg_state(&dev_priv->drm,
> + "Invalid Gamma LUT size. Expected %u, got %u.\n",
> + degamma_length, drm_color_lut_size(gamma_lut));
> + return -EINVAL;
> + }
>
> if (test_luts(degamma_lut, degamma_channels_tests) ||
> test_luts(gamma_lut, gamma_channels_tests))
> diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> index 4045e2507e11c..a22d32a7a8719 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -38,6 +38,7 @@ struct drm_atomic_state;
> struct drm_private_obj;
> struct drm_private_state;
>
> +int drm_atomic_helper_check_crtcs(struct drm_atomic_state *state);
> int drm_atomic_helper_check_modeset(struct drm_device *dev,
> struct drm_atomic_state *state);
> int drm_atomic_helper_check_plane_state(struct drm_plane_state *plane_state,
> diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
> index 3537f3eeb3872..cb2d74719f2d5 100644
> --- a/include/drm/drm_color_mgmt.h
> +++ b/include/drm/drm_color_mgmt.h
> @@ -74,6 +74,9 @@ static inline int drm_color_lut_size(const struct drm_property_blob *blob)
> return blob->length / sizeof(struct drm_color_lut);
> }
>
> +int drm_check_lut_size(const struct drm_property_blob *lut,
> + uint32_t expected_size);
> +
> enum drm_color_encoding {
> DRM_COLOR_YCBCR_BT601,
> DRM_COLOR_YCBCR_BT709,
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 2deb15d7e1610..4fd1c9a4bbba8 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -1072,6 +1072,17 @@ struct drm_crtc {
> /** @funcs: CRTC control functions */
> const struct drm_crtc_funcs *funcs;
>
> + /**
> + * @degamma_lut_size: Size of degamma LUT.
> + */
> + size_t degamma_lut_size;
> +
> + /**
> + * @gamma_lut_size: Size of Gamma LUT. Not used by legacy userspace such as
> + * X, which doesn't support large lut sizes.
> + */
> + size_t gamma_lut_size;
> +

On NVIDIA hardware, multiple LUT sizes are supported. We do this check in e.g.

drivers/gpu/drm/nouveau/dispnv50/base907c.c:base907c_ilut

So I don't think a single sizes at the CRTC level makes sense.

Cheers,

-ilia

> /**
> * @gamma_size: Size of legacy gamma ramp reported to userspace. Set up
> * by calling drm_mode_crtc_set_gamma_size().
> --
> 2.34.0.rc0.344.g81b53c2807-goog
>