[PATCH v2] drm/amdgpu: Ensure that the modifier requested is supported by plane.

[Mark Yacoub]

From: Mark Yacoub <markyacoub at google.com>

On initializing the framebuffer, call drm_any_plane_has_format to do a
check if the modifier is supported. drm_any_plane_has_format calls
dm_plane_format_mod_supported which is extended to validate that the
modifier is on the list of the plane's supported modifiers.

The bug was caught using igt-gpu-tools test: kms_addfb_basic.addfb25-bad-modifier

Tested on ChromeOS Zork by turning on the display, running an overlay
test, and running a YT video.

=== Changes from v1 ===
Explicitly handle DRM_FORMAT_MOD_INVALID modifier.

Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
Signed-off-by: default avatarMark Yacoub <markyacoub at chromium.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_display.c    | 13 +++++++++++++
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c  | 18 +++++++++++++++---
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
index afa5f8ad0f563..a947b5aa420d2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
@@ -908,6 +908,19 @@ int amdgpu_display_gem_fb_verify_and_init(
 					 &amdgpu_fb_funcs);
 	if (ret)
 		goto err;
+	/* Verify that the modifier is supported. */
+	if (!drm_any_plane_has_format(dev, mode_cmd->pixel_format,
+				      mode_cmd->modifier[0])) {
+		struct drm_format_name_buf format_name;
+		drm_dbg_kms(dev,
+			    "unsupported pixel format %s / modifier 0x%llx\n",
+			    drm_get_format_name(mode_cmd->pixel_format,
+						&format_name),
+			    mode_cmd->modifier[0]);
+
+		ret = -EINVAL;
+		goto err;
+	}
 
 	ret = amdgpu_display_framebuffer_init(dev, rfb, mode_cmd, obj);
 	if (ret)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 961abf1cf040c..6fc746996c24f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -3939,6 +3939,7 @@ static bool dm_plane_format_mod_supported(struct drm_plane *plane,
 {
 	struct amdgpu_device *adev = drm_to_adev(plane->dev);
 	const struct drm_format_info *info = drm_format_info(format);
+	int i;
 
 	enum dm_micro_swizzle microtile = modifier_gfx9_swizzle_mode(modifier) & 3;
 
@@ -3946,11 +3947,22 @@ static bool dm_plane_format_mod_supported(struct drm_plane *plane,
 		return false;
 
 	/*
-	 * We always have to allow this modifier, because core DRM still
-	 * checks LINEAR support if userspace does not provide modifers.
+	 * We always have to allow these modifiers: 
+	 * 1. Core DRM checks for LINEAR support if userspace does not provide modifiers. 
+	 * 2. Not passing any modifiers is the same as explicitly passing INVALID.
 	 */
-	if (modifier == DRM_FORMAT_MOD_LINEAR)
+	if (modifier == DRM_FORMAT_MOD_LINEAR ||
+	    modifier == DRM_FORMAT_MOD_INVALID) {
 		return true;
+	}
+
+	/* Check that the modifier is on the list of the plane's supported modifiers. */
+	for (i = 0; i < plane->modifier_count; i++) {
+		if (modifier == plane->modifiers[i])
+			break;
+	}
+	if (i == plane->modifier_count)
+		return false;
 
 	/*
 	 * The arbitrary tiling support for multiplane formats has not been hooked
-- 
2.31.0.291.g576ba9dcdaf-goog