Re: [PATCH 1/2] drm: Add Gamma and Degamma LUT sizes props to drm_crtc to validate.

Paul Menzel <pmenzel@xxxxxxxxxxxxx> · Tue, 26 Oct 2021 14:02:46 +0200

Dear Mark,


Thank you for your patch.

On 13.10.21 20:12, Mark Yacoub 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 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@xxxxxxxxxxxx>
---
  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@xxxxxxxxxxxxx>


Kind regards,

Paul






