Hi Dan,
Thank you for the patch.
On Mon, Dec 05, 2022 at 02:37:58PM +0000, Daniel Scally wrote:
The f_uvc code includes an interrupt endpoint against the VideoControl
interface. According to section 2.4.2 of the UVC specification however
this endpoint is optional in at least some cases:
"This endpoint is optional, but may be mandatory under certain
conditions"
The conditions enumerated are whether...
1. The device supports hardware triggers
2. The device implements any AutoUpdate controls
3. The device implements any Asynchronous controls
As all of those things are implementation dependent, this endpoint
might be unnecessary for some users. Check whether the user has
requested it be disable via configfs and don't proceed with its
s/disable/disabled/
instantiation if so.
Signed-off-by: Daniel Scally <dan.scally@xxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_uvc.c | 42 ++++++++++++++++++-----------
drivers/usb/gadget/function/uvc.h | 1 +
2 files changed, 27 insertions(+), 16 deletions(-)
diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 49b7231742d6..76ec84d3a5fd 100644
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -79,7 +79,7 @@ static struct usb_interface_descriptor uvc_control_intf = {
.bDescriptorType = USB_DT_INTERFACE,
.bInterfaceNumber = UVC_INTF_VIDEO_CONTROL,
.bAlternateSetting = 0,
- .bNumEndpoints = 1,
+ .bNumEndpoints = 0,
.bInterfaceClass = USB_CLASS_VIDEO,
.bInterfaceSubClass = UVC_SC_VIDEOCONTROL,
.bInterfaceProtocol = 0x00,
@@ -290,14 +290,16 @@ uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
if (alt)
return -EINVAL;
- uvcg_info(f, "reset UVC interrupt endpoint\n");
- usb_ep_disable(uvc->interrupt_ep);
+ if (!uvc->disable_interrupt_ep) {
+ uvcg_info(f, "reset UVC interrupt endpoint\n");
+ usb_ep_disable(uvc->interrupt_ep);
- if (!uvc->interrupt_ep->desc)
- if (config_ep_by_speed(cdev->gadget, f, uvc->interrupt_ep))
- return -EINVAL;
+ if (!uvc->interrupt_ep->desc)
+ if (config_ep_by_speed(cdev->gadget, f, uvc->interrupt_ep))
Line wrap would be nice.
if (config_ep_by_speed(cdev->gadget, f,
uvc->interrupt_ep))
+ return -EINVAL;
- usb_ep_enable(uvc->interrupt_ep);
+ usb_ep_enable(uvc->interrupt_ep);
+ }
if (uvc->state == UVC_STATE_DISCONNECTED) {
memset(&v4l2_event, 0, sizeof(v4l2_event));
@@ -375,7 +377,8 @@ uvc_function_disable(struct usb_function *f)
uvc->state = UVC_STATE_DISCONNECTED;
usb_ep_disable(uvc->video.ep);
- usb_ep_disable(uvc->interrupt_ep);
+ if (!uvc->disable_interrupt_ep)
+ usb_ep_disable(uvc->interrupt_ep);
}
/* --------------------------------------------------------------------------
@@ -523,8 +526,10 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
control_size = 0;
streaming_size = 0;
bytes = uvc_iad.bLength + uvc_control_intf.bLength
- + uvc_interrupt_ep.bLength + uvc_control_cs_ep.bLength
- + uvc_streaming_intf_alt0.bLength;
+ + uvc_control_cs_ep.bLength + uvc_streaming_intf_alt0.bLength;
Wrong indentation.
+
+ if (!uvc->disable_interrupt_ep)
+ bytes += uvc_interrupt_ep.bLength;
if (speed == USB_SPEED_SUPER) {
bytes += uvc_ss_control_comp.bLength;
@@ -569,7 +574,8 @@ uvc_copy_descriptors(struct uvc_device *uvc, enum usb_device_speed speed)
uvc_control_header->bInCollection = 1;
uvc_control_header->baInterfaceNr[0] = uvc->streaming_intf;
- UVC_COPY_DESCRIPTOR(mem, dst, &uvc_interrupt_ep);
+ if (!uvc->disable_interrupt_ep)
+ UVC_COPY_DESCRIPTOR(mem, dst, &uvc_interrupt_ep);
if (speed == USB_SPEED_SUPER)
UVC_COPY_DESCRIPTOR(mem, dst, &uvc_ss_control_comp);
This is the companion descriptor for the interrupt endpoint, it should
only be included if the interrupt endpoint is enabled. Same for
uvc_control_cs_ep.
@@ -656,12 +662,16 @@ uvc_function_bind(struct usb_configuration *c, struct usb_function *f)
(opts->streaming_maxburst + 1));
/* Allocate endpoints. */
- ep = usb_ep_autoconfig(cdev->gadget, &uvc_interrupt_ep);
- if (!ep) {
- uvcg_info(f, "Unable to allocate control EP\n");
- goto error;
+ if (!opts->disable_interrupt_ep) {
+ ep = usb_ep_autoconfig(cdev->gadget, &uvc_interrupt_ep);
+ if (!ep) {
+ uvcg_info(f, "Unable to allocate interrupt EP\n");
+ goto error;
+ }
+ uvc->interrupt_ep = ep;
+ uvc_control_intf.bNumEndpoints = 1;
}
- uvc->interrupt_ep = ep;
+ uvc->disable_interrupt_ep = opts->disable_interrupt_ep;
Given that you always test for !uvc->disable_interrupt_ep, how about
naming this enable_interrupt_ep and switching the tests ? I think
positive logic is more readable that double negation. I would then move
this line up, in order to test uvc->enable_interrupt_ep instead of
!opts->disable_interrupt_ep above.
