[PATCH 1/4] media: verisilicon: Support holding the CAPTURE buffer for MPEG-2

[Arun Iyengar via B4 Relay <devnull+aiyengar1990.gmail.com@kernel.org>]

From: Arun Iyengar <aiyengar1990@gmail.com>

An MPEG-2 frame can be coded as two field pictures, each decoded by its
own request. Both fields have to land in the same CAPTURE buffer: the
G1 and VPU2 back-ends already write a bottom field one line into the
destination buffer and use the current buffer as the reference for the
second field of a P picture, so the second field must be decoded into
the buffer that holds the first one.

Userspace asks for that with V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF, which
the driver only allows for H.264. GStreamer's v4l2slmpeg2dec sets it on
the first field of every field-coded frame, so queueing that request
fails ("Driver does not support holding capture buffer") and decoding
stops. On RK3588 none of the field-picture streams of the ISO/IEC
13818-4 main-profile conformance suite (sony-ct1..4, tcela-8/9/10/16/19,
hhi_burst_*) decoded.

Allow holding the CAPTURE buffer for MPEG-2 too. Job completion goes
through v4l2_m2m_buf_done_and_job_finish(), which already keeps a held
CAPTURE buffer queued until the last field has been decoded.

Fixes: 340ce50f75a6 ("media: hantro: Enable HOLD_CAPTURE_BUF for H.264")
Cc: stable@vger.kernel.org
Signed-off-by: Arun Iyengar <aiyengar1990@gmail.com>
---
 drivers/media/platform/verisilicon/hantro_v4l2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/verisilicon/hantro_v4l2.c b/drivers/media/platform/verisilicon/hantro_v4l2.c
index 83af9fa1ce94..822c4b371671 100644
--- a/drivers/media/platform/verisilicon/hantro_v4l2.c
+++ b/drivers/media/platform/verisilicon/hantro_v4l2.c
@@ -513,13 +513,13 @@ hantro_update_requires_hold_capture_buf(struct hantro_ctx *ctx, u32 fourcc)
 
 	switch (fourcc) {
 	case V4L2_PIX_FMT_JPEG:
-	case V4L2_PIX_FMT_MPEG2_SLICE:
 	case V4L2_PIX_FMT_VP8_FRAME:
 	case V4L2_PIX_FMT_HEVC_SLICE:
 	case V4L2_PIX_FMT_VP9_FRAME:
 		vq->subsystem_flags &= ~(VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF);
 		break;
 	case V4L2_PIX_FMT_H264_SLICE:
+	case V4L2_PIX_FMT_MPEG2_SLICE:
 		vq->subsystem_flags |= VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF;
 		break;
 	default:

-- 
2.55.0