Logitech C922 internal sof does not increases at a stable rate of 1KHz.
This causes that the device_sof and the host_sof run at different rates,
breaking the clock domain conversion algorithm. Eg:
30 (6) [-] none 30 614400 B 21.245557 21.395214 34.133 fps ts mono/SoE
31 (7) [-] none 31 614400 B 21.275327 21.427246 33.591 fps ts mono/SoE
32 (0) [-] none 32 614400 B 21.304739 21.459256 34.000 fps ts mono/SoE
33 (1) [-] none 33 614400 B 21.334324 21.495274 33.801 fps ts mono/SoE
* 34 (2) [-] none 34 614400 B 21.529237 21.527297 5.130 fps ts mono/SoE
* 35 (3) [-] none 35 614400 B 21.649416 21.559306 8.321 fps ts mono/SoE
36 (4) [-] none 36 614400 B 21.678789 21.595320 34.045 fps ts mono/SoE
...
99 (3) [-] none 99 614400 B 23.542226 23.696352 33.541 fps ts mono/SoE
100 (4) [-] none 100 614400 B 23.571578 23.728404 34.069 fps ts mono/SoE
101 (5) [-] none 101 614400 B 23.601425 23.760420 33.504 fps ts mono/SoE
* 102 (6) [-] none 102 614400 B 23.798324 23.796428 5.079 fps ts mono/SoE
* 103 (7) [-] none 103 614400 B 23.916271 23.828450 8.478 fps ts mono/SoE
104 (0) [-] none 104 614400 B 23.945720 23.860479 33.957 fps ts mono/SoE
Instead of disabling completely the hardware timestamping for such
hardware we take the assumption that the package handling jitter is
under 2ms and use the host_sof as dev_sof.
For the hardware tested, it provides a much better timestamping than a
pure software solution:
https://ibb.co/D1HJJ4x
https://ibb.co/8s9dBdk
https://ibb.co/QC9MgVK
This bug in the camera firmware has been confirmed by the vendor.
lsusb -v
Bus 001 Device 044: ID 046d:085c Logitech, Inc. C922 Pro Stream Webcam
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 239 Miscellaneous Device
bDeviceSubClass 2
bDeviceProtocol 1 Interface Association
bMaxPacketSize0 64
idVendor 0x046d Logitech, Inc.
idProduct 0x085c C922 Pro Stream Webcam
bcdDevice 0.16
iManufacturer 0
iProduct 2 C922 Pro Stream Webcam
iSerial 1 80B912DF
bNumConfigurations 1
Signed-off-by: Ricardo Ribalda <[email protected]>
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index 80ef0f0e04b0..4512316c8748 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -2880,6 +2880,15 @@ static const struct usb_device_id uvc_ids[] = {
.bInterfaceSubClass = 1,
.bInterfaceProtocol = 0,
.driver_info = UVC_INFO_QUIRK(UVC_QUIRK_RESTORE_CTRLS_ON_INIT) },
+ /* Logitech HD Pro Webcam C922 */
+ { .match_flags = USB_DEVICE_ID_MATCH_DEVICE
+ | USB_DEVICE_ID_MATCH_INT_INFO,
+ .idVendor = 0x046d,
+ .idProduct = 0x085c,
+ .bInterfaceClass = USB_CLASS_VIDEO,
+ .bInterfaceSubClass = 1,
+ .bInterfaceProtocol = 0,
+ .driver_info = UVC_INFO_QUIRK(UVC_QUIRK_INVALID_DEVICE_SOF) },
/* Chicony CNF7129 (Asus EEE 100HE) */
{ .match_flags = USB_DEVICE_ID_MATCH_DEVICE
| USB_DEVICE_ID_MATCH_INT_INFO,
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index a5b184e71ad7..d387d6335344 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -529,13 +529,20 @@ uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
* data packages of the same frame contains the same sof. In that case
* only the first one will match the host_sof.
*/
- dev_sof = get_unaligned_le16(&data[header_size - 2]);
+ if (stream->dev->quirks & UVC_QUIRK_INVALID_DEVICE_SOF)
+ dev_sof = usb_get_current_frame_number(stream->dev->udev);
+ else
+ dev_sof = get_unaligned_le16(&data[header_size - 2]);
+
if (dev_sof == stream->clock.last_sof)
return;
stream->clock.last_sof = dev_sof;
- host_sof = usb_get_current_frame_number(stream->dev->udev);
+ if (stream->dev->quirks & UVC_QUIRK_INVALID_DEVICE_SOF)
+ host_sof = dev_sof;
+ else
+ host_sof = usb_get_current_frame_number(stream->dev->udev);
time = uvc_video_get_time();
/*
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index f395b67fe95a..e41289605d0e 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -213,6 +213,7 @@
#define UVC_QUIRK_FORCE_Y8 0x00000800
#define UVC_QUIRK_FORCE_BPP 0x00001000
#define UVC_QUIRK_IGNORE_EMPTY_TS 0x00002000
+#define UVC_QUIRK_INVALID_DEVICE_SOF 0x00004000
/* Format flags */
#define UVC_FMT_FLAG_COMPRESSED 0x00000001
--
b4 0.11.0-dev-d93f8