On 04.11.26 23:11, Rob Clark wrote:
On Wed, Nov 4, 2026 at 11:00 AM Robert Mader <[email protected]> wrote:
Nice, very happy to see the series!
On 04.11.26 17:36, Dmitry Baryshkov wrote:
The comment describing the QC10C buffer layout calls it a compressed
P010. It is not:
If I'm not mistaken the display engine / the DRM side (including Mesa)
describes it as P010+QCOM_COMPRESSED as well, and so does my pending
Gstreamer MR [1] . So if we can't pretend that QC10C ==
P010+QCOM_COMPRESSED, then we probably need a DRM_FORMAT_TP10, wire that
up everywhere etc. OTOH if we want to keep the DRM side as is, then the
comment should reflect that, IMO.
IMHO we need DRM_FORMAT_TP10.. on the GPU side, we have TP10 and P010
as distinct formats, both with and without UBWC. I'm not sure if the
same is true on video side but P010+UBWC was never exposed, or if it
truely only supports linear P010 and UBWC TP10.
Oh, do I understand you correctly that the P010+UBWC implementation is
not compatible with QC10C, meaning on the GPU side (Mesa and display) we
don't yet have any support for QC10C exposed to userspace? If that's so
then we don't have a choice but to introduce DRM_FORMAT_TP10 I guess?
On the plus side - this would allow us to make the format single plane,
matching what we get on the V4L2 side.
BR,
-R
Best regards,
Robert
1: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8195
P010 stores each sample in 16 bits, QC10C packs three
10-bit samples in each 32-bit word, which is what the stride computed
below (width * 4 / 3) assumes. Name the format correctly.
Signed-off-by: Dmitry Baryshkov <[email protected]>
---
drivers/media/platform/qcom/iris/iris_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/platform/qcom/iris/iris_buffer.c
b/drivers/media/platform/qcom/iris/iris_buffer.c
index eb8de60c1177..ec2bf2a2d953 100644
--- a/drivers/media/platform/qcom/iris/iris_buffer.c
+++ b/drivers/media/platform/qcom/iris/iris_buffer.c
@@ -266,7 +266,7 @@ static u32 iris_yuv_buffer_size_qc08c(struct iris_inst
*inst)
/*
* QC10C:
- * UBWC-compressed format for P010.
+ * UBWC-compressed TP10, YUV 4:2:0 with three 10 bit samples packed in 32 bits.
* Contains 4 planes in the following order -
* (A) Y_Meta_Plane
* (B) Y_UBWC_Plane
--
Robert Mader
Consultant Software Developer
Collabora Ltd.
Platinum Building, St John's Innovation Park, Cambridge CB4 0DS, UK
Registered in England & Wales, no. 5513718
