Re: [PATCH V13 39/51] drm/amd/display: add 3x4 matrix colorop

[Tvrtko Ursulin <tursulin@ursulin.net>]

On 15/11/2025 00:02, Alex Hung wrote:
> This adds support for a 3x4 color transformation matrix.
> 
> With this change the following IGT tests pass:
> kms_colorop --run plane-XR30-XR30-ctm_3x4_50_desat
> kms_colorop --run plane-XR30-XR30-ctm_3x4_overdrive
> kms_colorop --run plane-XR30-XR30-ctm_3x4_oversaturate
> kms_colorop --run plane-XR30-XR30-ctm_3x4_bt709_enc
> kms_colorop --run plane-XR30-XR30-ctm_3x4_bt709_dec
> 
> The color pipeline now consists of the following colorops:
> 1. 1D curve colorop
> 2. 3x4 CTM
> 3. 1D curve colorop
> 4. 1D LUT
> 5. 1D curve colorop
> 6. 1D LUT
> 
> Signed-off-by: Alex Hung <alex.hung@amd.com>
> Signed-off-by: Harry Wentland <harry.wentland@amd.com>
> Reviewed-by: Daniel Stone <daniels@collabora.com>
> Reviewed-by: Melissa Wen <mwen@igalia.com>
> ---
> v13:
>   - Remove redundant ternary null check for drm_color_ctm_3x4 blob (Coverity Scan)
> 
> V10:
>   - Change %lu to %zu for sizeof() in drm_warn (kernel test robot)
>   - Remove redundant DRM_ERROR(...)
> 
> V9:
>   - Update function names by _plane_ (Chaitanya Kumar Borah)
> 
> v8:
>   - Return -EINVAL when drm_color_ctm_3x4's size mismatches (Leo Li)
> 
> v7:
>   - Change %lu to %zu for sizeof() in drm_warn
> 
> v6:
>   - fix warnings in dbg prints
> 
>   .../amd/display/amdgpu_dm/amdgpu_dm_color.c   | 52 +++++++++++++++++++
>   .../amd/display/amdgpu_dm/amdgpu_dm_colorop.c | 15 ++++++
>   2 files changed, 67 insertions(+)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> index b958f9c0a0c2..298f337f0eb4 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
> @@ -1378,6 +1378,47 @@ __set_dm_plane_colorop_degamma(struct drm_plane_state *plane_state,
>   	return __set_colorop_in_tf_1d_curve(dc_plane_state, colorop_state);
>   }
>   
> +static int
> +__set_dm_plane_colorop_3x4_matrix(struct drm_plane_state *plane_state,
> +				  struct dc_plane_state *dc_plane_state,
> +				  struct drm_colorop *colorop)
> +{
> +	struct drm_colorop *old_colorop;
> +	struct drm_colorop_state *colorop_state = NULL, *new_colorop_state;
> +	struct drm_atomic_state *state = plane_state->state;
> +	const struct drm_device *dev = colorop->dev;
> +	const struct drm_property_blob *blob;
> +	struct drm_color_ctm_3x4 *ctm = NULL;
> +	int i = 0;
> +
> +	/* 3x4 matrix */
> +	old_colorop = colorop;
> +	for_each_new_colorop_in_state(state, colorop, new_colorop_state, i) {
> +		if (new_colorop_state->colorop == old_colorop &&
> +		    new_colorop_state->colorop->type == DRM_COLOROP_CTM_3X4) {
> +			colorop_state = new_colorop_state;
> +			break;
> +		}
> +	}
> +
> +	if (colorop_state && !colorop_state->bypass && colorop->type == DRM_COLOROP_CTM_3X4) {
> +		drm_dbg(dev, "3x4 matrix colorop with ID: %d\n", colorop->base.id);
> +		blob = colorop_state->data;
> +		if (blob->length == sizeof(struct drm_color_ctm_3x4)) {
> +			ctm = (struct drm_color_ctm_3x4 *) blob->data;
> +			__drm_ctm_3x4_to_dc_matrix(ctm, dc_plane_state->gamut_remap_matrix.matrix);
> +			dc_plane_state->gamut_remap_matrix.enable_remap = true;
> +			dc_plane_state->input_csc_color_matrix.enable_adjustment = false;
> +		} else {
> +			drm_warn(dev, "blob->length (%zu) isn't equal to drm_color_ctm_3x4 (%zu)\n",
> +				 blob->length, sizeof(struct drm_color_ctm_3x4));
> +			return -EINVAL;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>   static int
>   __set_dm_plane_colorop_shaper(struct drm_plane_state *plane_state,
>   			      struct dc_plane_state *dc_plane_state,
> @@ -1581,6 +1622,17 @@ amdgpu_dm_plane_set_colorop_properties(struct drm_plane_state *plane_state,
>   	if (ret)
>   		return ret;
>   
> +	/* 3x4 matrix */
> +	colorop = colorop->next;
> +	if (!colorop) {
> +		drm_dbg(dev, "no 3x4 matrix colorop found\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = __set_dm_plane_colorop_3x4_matrix(plane_state, dc_plane_state, colorop);
> +	if (ret)
> +		return ret;
> +
>   	/* 1D Curve & LUT - SHAPER TF & LUT */
>   	colorop = colorop->next;
>   	if (!colorop) {
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_colorop.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_colorop.c
> index 4845f26e4a8a..f2be75b9b073 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_colorop.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_colorop.c
> @@ -74,6 +74,21 @@ int amdgpu_dm_initialize_default_pipeline(struct drm_plane *plane, struct drm_pr
>   
>   	i++;
>   
> +	/* 3x4 matrix */
> +	ops[i] = kzalloc(sizeof(struct drm_colorop), GFP_KERNEL);
> +	if (!ops[i]) {
> +		ret = -ENOMEM;
> +		goto cleanup;

Does this cleanup path leak the list->name allocated a few lines above, 
outside the diff? Kmemleak appears to think it can leak from somewhere 
at least:

unreferenced object 0xffff8881143c1e00 (size 32):
   comm "(udev-worker)", pid 588, jiffies 4294888494
   hex dump (first 32 bytes):
     43 6f 6c 6f 72 20 50 69 70 65 6c 69 6e 65 20 33  Color Pipeline 3
     31 33 00 00 00 00 00 00 00 00 00 00 00 00 00 00  13..............
   backtrace (crc a75af242):
     __kmalloc_node_track_caller_noprof+0x525/0x890
     kvasprintf+0xb6/0x130
     kasprintf+0xb2/0xe0
     amdgpu_dm_initialize_default_pipeline+0x1ce/0x840 [amdgpu]
     dm_plane_init_colorops+0x19c/0x2e0 [amdgpu]
     amdgpu_dm_plane_init+0x4c4/0xf10 [amdgpu]
     initialize_plane+0xf1/0x280 [amdgpu]
     amdgpu_dm_init+0x23d0/0x7450 [amdgpu]
     dm_hw_init+0x3d/0x200 [amdgpu]
     amdgpu_device_init+0x67cd/0x9b20 [amdgpu]
     amdgpu_driver_load_kms+0x13/0xf0 [amdgpu]
     amdgpu_pci_probe+0x437/0xf30 [amdgpu]
     local_pci_probe+0xda/0x180
     pci_device_probe+0x381/0x730
     really_probe+0x1da/0x970
     __driver_probe_device+0x18c/0x3e0

Could it be a false positive, or leaking later after the success path, 
or some other path I am not sure since I am not at home in this code.

There is no error checking on list->name either, so I supppose the code 
which can touch that can handle a NULL harmlessly?

Regards,

Tvrtko

> +	}
> +
> +	ret = drm_plane_colorop_ctm_3x4_init(dev, ops[i], plane);
> +	if (ret)
> +		goto cleanup;
> +
> +	drm_colorop_set_next_property(ops[i-1], ops[i]);
> +
> +	i++;
> +
>   	/* 1D curve - SHAPER TF */
>   	ops[i] = kzalloc(sizeof(struct drm_colorop), GFP_KERNEL);
>   	if (!ops[i]) {