[PATCH v2 2/2] drm/amd/display: Use drm_edid_block_count() instead of raw extensions

["Timo Prömer" <timo.proemer04@gmail.com>]

From: Timoyoungster <timo.proemer04@gmail.com>

Instead of manually calculating the EDID block count by reading the
extensions field from the raw edid structure (`edid->extensions + 1`),
utilize the core DRM helper `drm_edid_block_count()`.

This now includes possible HF-EEODB extension blocks, which are not
included in `edid->extensions` and were previously truncated with the
`memmove`.

Signed-off-by: Timo Prömer <timo.proemer04@gmail.com>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index c6f94eb71..d6d6ea719 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -1160,6 +1160,7 @@ enum dc_edid_status dm_helpers_read_local_edid(
 	struct drm_connector *connector = &aconnector->base;
 	struct i2c_adapter *ddc;
 	int retry = 25;
+	int block_count;
 	enum dc_edid_status edid_status = EDID_NO_RESPONSE;
 	const struct drm_edid *drm_edid;
 	const struct edid *edid;
@@ -1201,11 +1202,15 @@ enum dc_edid_status dm_helpers_read_local_edid(
 			continue;
 
 		edid = drm_edid_raw(drm_edid); // FIXME: Get rid of drm_edid_raw()
-		if (!edid ||
-		    edid->extensions >= sizeof(sink->dc_edid.raw_edid) / EDID_LENGTH)
+		if (!edid)
 			return EDID_BAD_INPUT;
 
-		sink->dc_edid.length = EDID_LENGTH * (edid->extensions + 1);
+		block_count = drm_edid_block_count(drm_edid);
+
+		if (block_count > sizeof(sink->dc_edid.raw_edid) / EDID_LENGTH)
+			return EDID_BAD_INPUT;
+
+		sink->dc_edid.length = EDID_LENGTH * block_count;
 		memmove(sink->dc_edid.raw_edid, (uint8_t *)edid, sink->dc_edid.length);
 
 		/* We don't need the original edid anymore */
-- 
2.55.0