Re: [PATCH v2 4/4] media: aspeed: Fix timing polarity incorrect
From: Hans Verkuil <hidden>
Date: 2022-01-21 07:30:27
Also in:
linux-aspeed, linux-media, lkml, openbmc
On 12/22/21 09:21, Jammy Huang wrote:
This is a workaround for sync polarity unstable. Sync value get by VR09C counts from sync's rising edge, which means sync's polarity is negative if sync value is bigger than total/2.
Do you have an example of such a format, or is this mostly theoretical? Either provide the example or make a note that it is theoretical. Regards, Hans
quoted hunk ↗ jump to hunk
Signed-off-by: Jammy Huang <redacted> --- v2: - Use 'total/2' rather than 'total<<1' - Update comment --- drivers/media/platform/aspeed-video.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c index 7c50567f5ab0..c3e3343d91e1 100644 --- a/drivers/media/platform/aspeed-video.c +++ b/drivers/media/platform/aspeed-video.c@@ -989,6 +989,16 @@ static void aspeed_video_get_resolution(struct aspeed_video *video) video->frame_bottom = FIELD_GET(VE_SRC_TB_EDGE_DET_BOT, src_tb_edge); video->frame_top = FIELD_GET(VE_SRC_TB_EDGE_DET_TOP, src_tb_edge); + + /* + * This is a workaround for polarity detection when the sync + * value is larger than half. + */ + if (vsync > (vtotal / 2)) + det->polarities &= ~V4L2_DV_VSYNC_POS_POL; + else + det->polarities |= V4L2_DV_VSYNC_POS_POL; + if (det->polarities & V4L2_DV_VSYNC_POS_POL) { det->vbackporch = video->frame_top - vsync; det->vfrontporch = vtotal - video->frame_bottom;@@ -1003,6 +1013,16 @@ static void aspeed_video_get_resolution(struct aspeed_video *video) video->frame_right = FIELD_GET(VE_SRC_LR_EDGE_DET_RT, src_lr_edge); video->frame_left = FIELD_GET(VE_SRC_LR_EDGE_DET_LEFT, src_lr_edge); + + /* + * This is a workaround for polarity detection when the sync + * value is larger than half. + */ + if (hsync > (htotal / 2)) + det->polarities &= ~V4L2_DV_HSYNC_POS_POL; + else + det->polarities |= V4L2_DV_HSYNC_POS_POL; + if (det->polarities & V4L2_DV_HSYNC_POS_POL) { det->hbackporch = video->frame_left - hsync; det->hfrontporch = htotal - video->frame_right;
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