Thread (83 messages) 83 messages, 3 authors, 2025-12-19

Re: [PATCH RESEND v2 15/32] drm/vkms: Introduce configfs for plane color range

From: "Luca Ceresoli" <luca.ceresoli@bootlin.com>
Date: 2025-12-18 18:00:56
Also in: dri-devel, lkml

On Wed Oct 29, 2025 at 3:36 PM CET, Louis Chauvet wrote:
To allows the userspace to test many hardware configuration, introduce a
new interface to configure the available color ranges per planes. VKMS
supports multiple color ranges, so the userspace can choose any
combination.

The supported color ranges are configured by writing a color range bitmask
to the file `supported_color_ranges` and the default color range is
chosen by writing a color encoding bitmask to `default_color_range`.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
quoted hunk ↗ jump to hunk
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index ee2e8d141f9e..3f658dd41272 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -439,6 +439,91 @@ static ssize_t plane_default_rotation_store(struct config_item *item,
 	return count;
 }

+static ssize_t plane_supported_color_ranges_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int supported_color_range;
                     supported_color_ranges
+
+	plane = plane_item_to_vkms_configfs_plane(item);
As for previous patches, set this on declaration for consistency (same below).
+static ssize_t plane_supported_color_ranges_store(struct config_item *item,
+						  const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~(BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
+		    BIT(DRM_COLOR_YCBCR_FULL_RANGE)))
+		return -EINVAL;
+	/* Should at least provide one color range */
+	if ((val & (BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
+		    BIT(DRM_COLOR_YCBCR_FULL_RANGE))) == 0)
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		/* Ensures that the default rotation is included in supported rotation */
Oh no, that comment again! :-)
+static ssize_t plane_default_color_range_store(struct config_item *item,
+					       const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~(BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
+		    BIT(DRM_COLOR_YCBCR_FULL_RANGE)))
+		return -EINVAL;
+	/* Should at least provide one color range */
+	if ((val & (BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
+		    BIT(DRM_COLOR_YCBCR_FULL_RANGE))) == 0)
+		return -EINVAL;
As in patch 12, replace this with is_power_of_2() to check that exactly one
bit is set.

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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