diff options
Diffstat (limited to 'drivers/media/usb/uvc/uvc_video.c')
| -rw-r--r-- | drivers/media/usb/uvc/uvc_video.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c index 7cbf4692bd..51f4f653b9 100644 --- a/drivers/media/usb/uvc/uvc_video.c +++ b/drivers/media/usb/uvc/uvc_video.c @@ -529,6 +529,17 @@ uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf, stream->clock.last_sof = dev_sof; host_sof = usb_get_current_frame_number(stream->dev->udev); + + /* + * On some devices, like the Logitech C922, the device SOF does not run + * at a stable rate of 1kHz. For those devices use the host SOF instead. + * In the tests performed so far, this improves the timestamp precision. + * This is probably explained by a small packet handling jitter from the + * host, but the exact reason hasn't been fully determined. + */ + if (stream->dev->quirks & UVC_QUIRK_INVALID_DEVICE_SOF) + dev_sof = host_sof; + time = uvc_video_get_time(); /* @@ -709,11 +720,11 @@ void uvc_video_clock_update(struct uvc_streaming *stream, unsigned long flags; u64 timestamp; u32 delta_stc; - u32 y1, y2; + u32 y1; u32 x1, x2; u32 mean; u32 sof; - u64 y; + u64 y, y2; if (!uvc_hw_timestamps_param) return; @@ -753,7 +764,7 @@ void uvc_video_clock_update(struct uvc_streaming *stream, sof = y; uvc_dbg(stream->dev, CLOCK, - "%s: PTS %u y %llu.%06llu SOF %u.%06llu (x1 %u x2 %u y1 %u y2 %u SOF offset %u)\n", + "%s: PTS %u y %llu.%06llu SOF %u.%06llu (x1 %u x2 %u y1 %u y2 %llu SOF offset %u)\n", stream->dev->name, buf->pts, y >> 16, div_u64((y & 0xffff) * 1000000, 65536), sof >> 16, div_u64(((u64)sof & 0xffff) * 1000000LLU, 65536), @@ -768,7 +779,7 @@ void uvc_video_clock_update(struct uvc_streaming *stream, goto done; y1 = NSEC_PER_SEC; - y2 = (u32)ktime_to_ns(ktime_sub(last->host_time, first->host_time)) + y1; + y2 = ktime_to_ns(ktime_sub(last->host_time, first->host_time)) + y1; /* * Interpolated and host SOF timestamps can wrap around at slightly @@ -789,7 +800,7 @@ void uvc_video_clock_update(struct uvc_streaming *stream, timestamp = ktime_to_ns(first->host_time) + y - y1; uvc_dbg(stream->dev, CLOCK, - "%s: SOF %u.%06llu y %llu ts %llu buf ts %llu (x1 %u/%u/%u x2 %u/%u/%u y1 %u y2 %u)\n", + "%s: SOF %u.%06llu y %llu ts %llu buf ts %llu (x1 %u/%u/%u x2 %u/%u/%u y1 %u y2 %llu)\n", stream->dev->name, sof >> 16, div_u64(((u64)sof & 0xffff) * 1000000LLU, 65536), y, timestamp, vbuf->vb2_buf.timestamp, |