2021-03-08 12:57:42

by Pawel Laszczak

Subject: [PATCH v2] usb: gadget: uvc: add bInterval checking for HS mode

From: Pawel Laszczak <[email protected]>

Patch adds extra checking for bInterval passed by configfs.
The 5.6.4 chapter of USB Specification (rev. 2.0) say:
"A high-bandwidth endpoint must specify a period of 1x125 µs
(i.e., a bInterval value of 1)."

The issue was observed during testing UVC class on CV.
I treat this change as improvement because we can control
bInterval by configfs.

Signed-off-by: Pawel Laszczak <[email protected]>

---
Changlog:
v2:
- removed duplicated assignment

drivers/usb/gadget/function/f_uvc.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 44b4352a2676..ed77a126a74f 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -633,7 +633,12 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)

uvc_hs_streaming_ep.wMaxPacketSize =
cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));
- uvc_hs_streaming_ep.bInterval = opts->streaming_interval;
+
+ /* A high-bandwidth endpoint must specify a bInterval value of 1 */
+ if (max_packet_mult > 1)
+ uvc_hs_streaming_ep.bInterval = 1;
+ else
+ uvc_hs_streaming_ep.bInterval = opts->streaming_interval;

uvc_ss_streaming_ep.wMaxPacketSize = cpu_to_le16(max_packet_size);
uvc_ss_streaming_ep.bInterval = opts->streaming_interval;
--
2.25.1

2021-03-14 02:31:11

by Peter Chen

Subject: Re: [PATCH v2] usb: gadget: uvc: add bInterval checking for HS mode

On 21-03-08 13:53:38, Pawel Laszczak wrote:
> From: Pawel Laszczak <[email protected]>
>
> Patch adds extra checking for bInterval passed by configfs.
> The 5.6.4 chapter of USB Specification (rev. 2.0) say:
> "A high-bandwidth endpoint must specify a period of 1x125 ?s
> (i.e., a bInterval value of 1)."
>
> The issue was observed during testing UVC class on CV.
> I treat this change as improvement because we can control
> bInterval by configfs.
>
> Signed-off-by: Pawel Laszczak <[email protected]>
>
> ---
> Changlog:
> v2:
> - removed duplicated assignment
>
> drivers/usb/gadget/function/f_uvc.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
> index 44b4352a2676..ed77a126a74f 100644
> --- a/drivers/usb/gadget/function/f_uvc.c
> +++ b/drivers/usb/gadget/function/f_uvc.c
> @@ -633,7 +633,12 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
>
> uvc_hs_streaming_ep.wMaxPacketSize =
> cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));
> - uvc_hs_streaming_ep.bInterval = opts->streaming_interval;
> +
> + /* A high-bandwidth endpoint must specify a bInterval value of 1 */
> + if (max_packet_mult > 1)
> + uvc_hs_streaming_ep.bInterval = 1;
> + else
> + uvc_hs_streaming_ep.bInterval = opts->streaming_interval;
>
> uvc_ss_streaming_ep.wMaxPacketSize = cpu_to_le16(max_packet_size);
> uvc_ss_streaming_ep.bInterval = opts->streaming_interval;
> --
> 2.25.1
>

Reviewed-by: Peter Chen <[email protected]>

--

Thanks,
Peter Chen

2021-03-14 02:45:42

by Laurent Pinchart

Subject: Re: [PATCH v2] usb: gadget: uvc: add bInterval checking for HS mode

Hi Pawel,

Thank you for the patch.

On Mon, Mar 08, 2021 at 01:53:38PM +0100, Pawel Laszczak wrote:
> From: Pawel Laszczak <[email protected]>
>
> Patch adds extra checking for bInterval passed by configfs.
> The 5.6.4 chapter of USB Specification (rev. 2.0) say:
> "A high-bandwidth endpoint must specify a period of 1x125 µs
> (i.e., a bInterval value of 1)."
>
> The issue was observed during testing UVC class on CV.
> I treat this change as improvement because we can control
> bInterval by configfs.
>
> Signed-off-by: Pawel Laszczak <[email protected]>

Reviewed-by: Laurent Pinchart <[email protected]>

Felipe, could you take this patch in your tree ?

> ---
> Changlog:
> v2:
> - removed duplicated assignment
>
> drivers/usb/gadget/function/f_uvc.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
> index 44b4352a2676..ed77a126a74f 100644
> --- a/drivers/usb/gadget/function/f_uvc.c
> +++ b/drivers/usb/gadget/function/f_uvc.c
> @@ -633,7 +633,12 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
>
> uvc_hs_streaming_ep.wMaxPacketSize =
> cpu_to_le16(max_packet_size | ((max_packet_mult - 1) << 11));
> - uvc_hs_streaming_ep.bInterval = opts->streaming_interval;
> +
> + /* A high-bandwidth endpoint must specify a bInterval value of 1 */
> + if (max_packet_mult > 1)
> + uvc_hs_streaming_ep.bInterval = 1;
> + else
> + uvc_hs_streaming_ep.bInterval = opts->streaming_interval;
>
> uvc_ss_streaming_ep.wMaxPacketSize = cpu_to_le16(max_packet_size);
> uvc_ss_streaming_ep.bInterval = opts->streaming_interval;

--
Regards,

Laurent Pinchart