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Message-ID: <cb482b45-d98c-1860-6cf2-313b831e6066@molgen.mpg.de>
Date:   Tue, 26 Oct 2021 14:02:46 +0200
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Subject: Re: [PATCH 1/2] drm: Add Gamma and Degamma LUT sizes props to
 drm_crtc to validate.
Content-Language: en-US
To:     Mark Yacoub <markyacoub@chromium.org>
Cc:     seanpaul@chromium.org, harry.wentland@amd.com,
        Mark Yacoub <markyacoub@google.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org,
        dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org,
        intel-gfx@lists.freedesktop.org
References: <20210929194012.3433306-1-markyacoub@chromium.org>
 <20211013181228.1578201-1-markyacoub@chromium.org>
From:   Paul Menzel <pmenzel@molgen.mpg.de>
In-Reply-To: <20211013181228.1578201-1-markyacoub@chromium.org>
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Dear Mark,


Thank you for your patch.

On 13.10.21 20:12, Mark Yacoub wrote:
> From: Mark Yacoub <markyacoub@google.com>
> 
> [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 can the problem be reproduced?

> [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. Rename older lut checks that test for the color channels to indicate
> it's a channel check. It's not included in drm_atomic_helper_check_crtc
> as it's hardware specific and is to be called by the driver.
> 4. As the LUT size check now happens in drm_atomic_helper_check, remove
> the lut check in intel_color.c
> 
> Fixes: igt@kms_color@pipe-A-invalid-gamma-lut-sizes on MTK

If I am not mistaken, the Fixes tag is used for commits I believe. Maybe 
use Resolves or something similar?

> Tested on Zork(amdgpu) and Jacuzzi(mediatek), volteer(TGL)

Please add a space before the (.

How did you test this?

> 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@chromium.org>
> ---
>   drivers/gpu/drm/drm_atomic_helper.c        | 60 ++++++++++++++++++++++
>   drivers/gpu/drm/drm_color_mgmt.c           | 14 ++---
>   drivers/gpu/drm/i915/display/intel_color.c | 14 ++---
>   include/drm/drm_atomic_helper.h            |  1 +
>   include/drm/drm_color_mgmt.h               |  7 +--
>   include/drm/drm_crtc.h                     | 11 ++++
>   6 files changed, 89 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index bc3487964fb5e..5feb2ad0209c3 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -929,6 +929,62 @@ 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 &&
> +		    new_crtc_state->gamma_lut) {
> +			uint64_t supported_lut_size = crtc->gamma_lut_size;
> +			uint32_t supported_legacy_lut_size = crtc->gamma_size;
> +			uint32_t new_state_lut_size =
> +				drm_color_lut_size(new_crtc_state->gamma_lut);
> +
> +			if (new_state_lut_size != supported_lut_size &&
> +			    new_state_lut_size != supported_legacy_lut_size) {
> +				drm_dbg_state(
> +					state->dev,
> +					"Invalid Gamma LUT size. Should be %u (or %u for legacy) but got %u.\n",
> +					supported_lut_size,
> +					supported_legacy_lut_size,
> +					new_state_lut_size);
> +				return -EINVAL;
> +			}
> +		}
> +
> +		if (new_crtc_state->color_mgmt_changed &&
> +		    new_crtc_state->degamma_lut) {
> +			uint32_t new_state_lut_size =
> +				drm_color_lut_size(new_crtc_state->degamma_lut);
> +			uint64_t supported_lut_size = crtc->degamma_lut_size;
> +
> +			if (new_state_lut_size != supported_lut_size) {
> +				drm_dbg_state(
> +					state->dev,
> +					"Invalid Degamma LUT size. Should be %u but got %u.\n",
> +					supported_lut_size, new_state_lut_size);
> +				return -EINVAL;
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_check_crtcs);
> +
>   /**
>    * drm_atomic_helper_check - validate state object
>    * @dev: DRM device
> @@ -974,6 +1030,10 @@ 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 bb14f488c8f6c..e5b820ce823bf 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,
> @@ -585,17 +587,17 @@ int drm_plane_create_color_properties(struct drm_plane *plane,
>   EXPORT_SYMBOL(drm_plane_create_color_properties);
>   
>   /**
> - * drm_color_lut_check - check validity of lookup table
> + * drm_color_lut_channels_check - check validity of the channels in the lookup table
>    * @lut: property blob containing LUT to check
>    * @tests: bitmask of tests to run
>    *
> - * Helper to check whether a userspace-provided lookup table is valid and
> - * satisfies hardware requirements.  Drivers pass a bitmask indicating which of
> - * the tests in &drm_color_lut_tests should be performed.
> + * Helper to check whether each color channel of userspace-provided lookup table is valid and
> + * satisfies hardware requirements. Drivers pass a bitmask indicating which of in
> + * &drm_color_lut_channels_tests should be performed.
>    *
>    * Returns 0 on success, -EINVAL on failure.
>    */
> -int drm_color_lut_check(const struct drm_property_blob *lut, u32 tests)
> +int drm_color_lut_channels_check(const struct drm_property_blob *lut, u32 tests)
>   {
>   	const struct drm_color_lut *entry;
>   	int i;
> @@ -625,4 +627,4 @@ int drm_color_lut_check(const struct drm_property_blob *lut, u32 tests)
>   
>   	return 0;
>   }
> -EXPORT_SYMBOL(drm_color_lut_check);
> +EXPORT_SYMBOL(drm_color_lut_channels_check);
> diff --git a/drivers/gpu/drm/i915/display/intel_color.c b/drivers/gpu/drm/i915/display/intel_color.c
> index dab892d2251ba..a308fe52746ac 100644
> --- a/drivers/gpu/drm/i915/display/intel_color.c
> +++ b/drivers/gpu/drm/i915/display/intel_color.c
> @@ -1285,7 +1285,7 @@ static int check_luts(const struct intel_crtc_state *crtc_state)
>   	const struct drm_property_blob *gamma_lut = crtc_state->hw.gamma_lut;
>   	const struct drm_property_blob *degamma_lut = crtc_state->hw.degamma_lut;
>   	int gamma_length, degamma_length;
> -	u32 gamma_tests, degamma_tests;
> +	u32 gamma_channels_tests, degamma_channels_tests;
>   
>   	/* Always allow legacy gamma LUT with no further checking. */
>   	if (crtc_state_is_legacy_gamma(crtc_state))
> @@ -1300,15 +1300,11 @@ static int check_luts(const struct intel_crtc_state *crtc_state)
>   
>   	degamma_length = INTEL_INFO(dev_priv)->color.degamma_lut_size;
>   	gamma_length = INTEL_INFO(dev_priv)->color.gamma_lut_size;
> -	degamma_tests = INTEL_INFO(dev_priv)->color.degamma_lut_tests;
> -	gamma_tests = INTEL_INFO(dev_priv)->color.gamma_lut_tests;
> +	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))
> -		return -EINVAL;
> -
> -	if (drm_color_lut_check(degamma_lut, degamma_tests) ||
> -	    drm_color_lut_check(gamma_lut, gamma_tests))
> +	if (drm_color_lut_channels_check(degamma_lut, degamma_channels_tests) ||
> +	    drm_color_lut_channels_check(gamma_lut, gamma_channels_tests))
>   		return -EINVAL;
>   
>   	return 0;
> 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 81c298488b0c8..cb1bf361ad3e3 100644
> --- a/include/drm/drm_color_mgmt.h
> +++ b/include/drm/drm_color_mgmt.h
> @@ -94,12 +94,12 @@ int drm_plane_create_color_properties(struct drm_plane *plane,
>   				      enum drm_color_range default_range);
>   
>   /**
> - * enum drm_color_lut_tests - hw-specific LUT tests to perform
> + * enum drm_color_lut_channels_tests - hw-specific LUT tests to perform
>    *
>    * The drm_color_lut_check() function takes a bitmask of the values here to
>    * determine which tests to apply to a userspace-provided LUT.
>    */
> -enum drm_color_lut_tests {
> +enum drm_color_lut_channels_tests {
>   	/**
>   	 * @DRM_COLOR_LUT_EQUAL_CHANNELS:
>   	 *
> @@ -119,5 +119,6 @@ enum drm_color_lut_tests {
>   	DRM_COLOR_LUT_NON_DECREASING = BIT(1),
>   };
>   
> -int drm_color_lut_check(const struct drm_property_blob *lut, u32 tests);
> +int drm_color_lut_channels_check(const struct drm_property_blob *lut,
> +				 u32 tests);
>   #endif
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index 2deb15d7e1610..cabd3ef1a6e32 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.
> +	 */
> +	uint32_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.
> +	 */
> +	uint32_t gamma_lut_size;
> +
>   	/**
>   	 * @gamma_size: Size of legacy gamma ramp reported to userspace. Set up
>   	 * by calling drm_mode_crtc_set_gamma_size().
> 

Acked-by: Paul Menzel <pmenzel@molgen.mpg.de>


Kind regards,

Paul