[PATCH AUTOSEL 4.19 03/21] usb: gadget: uvc: add bInterval checking for HS mode
From: Sasha Levin <sashal@kernel.org>
Date: 2021-05-02 14:08:00
Also in:
linux-usb, lkml
Subsystem:
the rest, usb subsystem, usb webcam gadget · Maintainers:
Linus Torvalds, Greg Kroah-Hartman
From: Pawel Laszczak <pawell@cadence.com> [ Upstream commit 26adde04acdff14a1f28d4a5dce46a8513a3038b ] 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. Reviewed-by: Peter Chen <peter.chen@kernel.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Pawel Laszczak <pawell@cadence.com> Link: https://lore.kernel.org/r/20210308125338.4824-1-pawell@gli-login.cadence.com (local) Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 d8ce7868fe22..169e73ed128c 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c@@ -645,7 +645,12 @@ 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;
--
2.30.2