Hi Ricardo,
Thank you for the patch.
On Wed, Jan 04, 2023 at 11:45:21AM +0100, Ricardo Ribalda wrote:
> Some SunplusIT cameras took a borderline interpretation of the UVC 1.5
> standard, and fill the PTS and SCR fields with invalid data if the
> package does not contain data.
>
> "STC must be captured when the first video data of a video frame is put
> on the USB bus."
>
> Eg:
>
> buffer: 0xa7755c00 len 000012 header:0x8c stc 00000000 sof 0000 pts 00000000
> buffer: 0xa7755c00 len 000012 header:0x8c stc 00000000 sof 0000 pts 00000000
> buffer: 0xa7755c00 len 000668 header:0x8c stc 73779dba sof 070c pts 7376d37a
>
> This borderline/buggy interpretation has been implemented in a variety
> of devices, from directly SunplusIT and from other OEMs that rebrand
> SunplusIT products.
>
> Luckily we can identify the affected modules by looking at the guid of
> one of the extension units:
>
> VideoControl Interface Descriptor:
> guidExtensionCode {82066163-7050-ab49-b8cc-b3855e8d221d}
>
> This patch adds a new quirk to take care of this.
>
> lsusb of one of the affected cameras:
>
> Bus 001 Device 003: ID 1bcf:2a01 Sunplus Innovation Technology Inc.
> Device Descriptor:
> bLength 18
> bDescriptorType 1
> bcdUSB 2.01
> bDeviceClass 239 Miscellaneous Device
> bDeviceSubClass 2 ?
> bDeviceProtocol 1 Interface Association
> bMaxPacketSize0 64
> idVendor 0x1bcf Sunplus Innovation Technology Inc.
> idProduct 0x2a01
> bcdDevice 0.02
> iManufacturer 1 SunplusIT Inc
> iProduct 2 HanChen Wise Camera
> iSerial 3 01.00.00
> bNumConfigurations 1
>
> Tested-by: HungNien Chen <hn.chen@xxxxxxxxxxxxx>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_driver.c | 11 +++++++++++
> drivers/media/usb/uvc/uvc_video.c | 10 ++++++++++
> drivers/media/usb/uvc/uvcvideo.h | 1 +
> 3 files changed, 22 insertions(+)
>
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index 5448576a8413..c5ab6e2d24c3 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -1199,6 +1199,17 @@ static const struct uvc_entity_quirk {
> u8 guid[16];
> u32 quirks;
> } uvc_entity_quirk[] = {
> + /*
> + * Some SunPlusIT uvc 1.5 device firmware expects that packages with
> + * no frame data are ignored by the host. Therefore it does not clear
> + * the PTS/SCR bits in the header, and breaks the timestamp decode
> + * algorithm.
> + */
> + {
> + .guid = {0x82, 0x06, 0x61, 0x63, 0x70, 0x50, 0xab, 0x49,
> + 0xb8, 0xcc, 0xb3, 0x85, 0x5e, 0x8d, 0x22, 0x1d},
> + .quirks = UVC_QUIRK_IGNORE_EMPTY_TS,
> + },
> };
>
> static void uvc_entity_quirks(struct uvc_device *dev)
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index def079c7a6fd..f469c62bedca 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -500,6 +500,16 @@ uvc_video_clock_decode(struct uvc_streaming *stream, struct uvc_buffer *buf,
> if (len < header_size)
> return;
>
> + /*
> + * Some devices make a borderline interpreation of the UVC 1.5 standard
s/interpreation/interpretation/
> + * and the packets with no data contain undefined timestamps. Ignore
"and send packets with no data ..." ?
> + * such packages to avoid interfering with the clock interpolation
s/packages/packets/
> + * algorithm.
> + */
> + if (stream->dev->quirks & UVC_QUIRK_IGNORE_EMPTY_TS &&
> + len == header_size)
> + return;
I've sent a reply to v2 which I'll copy here:
Given that there may be no guarantee that the above GUID won't be used
by devices that don't exhibit this problem, I'm wondering if we couldn't
use a heuristics instead of a quirk. I'm thinking about something along
the lines of
if (buf->bytesused == 0 && len == header_size && has_scr &&
stc == 0 && sof == 0)
This will catch suspicious SCR values (stc == 0 && sof == 0) on empty
packets (len == header_size) sent before any data packet (buf->bytesused
== 0), which should handle the devices you have to support, and avoid
false positives (the stc == 0 && sof == 0 check is already quite
restrictive, adding buf->bytesused == 0 would limit the workaround to
packets before the first data packet).
With this we could drop patch 2/8.
> +
> /*
> * Extract the timestamps:
> *
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index df93db259312..c3424ae29339 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -74,6 +74,7 @@
> #define UVC_QUIRK_RESTORE_CTRLS_ON_INIT 0x00000400
> #define UVC_QUIRK_FORCE_Y8 0x00000800
> #define UVC_QUIRK_FORCE_BPP 0x00001000
> +#define UVC_QUIRK_IGNORE_EMPTY_TS 0x00002000
>
> /* Format flags */
> #define UVC_FMT_FLAG_COMPRESSED 0x00000001
--
Regards,
Laurent Pinchart
