| Message ID | 20240403-uvc_request_length_by_interval-v4-10-ca22f334226e@pengutronix.de (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | usb: gadget: uvc: effectively fill the udc isoc pipeline with available video buffers | expand |
On Tue, Aug 13, 2024 at 11:09:34AM +0200, Michael Grzeschik wrote: > We increase the minimum amount of v4l2 buffers that will be possibly > enqueued into the hardware and allocate at least > UVCG_STREAMING_MIN_BUFFERS amount of requests. This way the driver has > also more requests available to prefill the isoc hardware with. > > Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> > > --- > v3 -> v4: - > v1 -> v3: new patch > --- > drivers/usb/gadget/function/uvc.h | 2 ++ > drivers/usb/gadget/function/uvc_queue.c | 3 ++- > drivers/usb/gadget/function/uvc_v4l2.c | 13 +++++++++++++ > 3 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h > index f6bc58fb02b84..e0b1f78fdbc65 100644 > --- a/drivers/usb/gadget/function/uvc.h > +++ b/drivers/usb/gadget/function/uvc.h > @@ -71,6 +71,8 @@ extern unsigned int uvc_gadget_trace_param; > > #define UVCG_REQUEST_HEADER_LEN 12 > > +#define UVCG_STREAMING_MIN_BUFFERS 4 > + 4 is a large number that drastically increases latency. > /* ------------------------------------------------------------------------ > * Structures > */ > diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c > index e33ce72325031..157e7f7d49c7a 100644 > --- a/drivers/usb/gadget/function/uvc_queue.c > +++ b/drivers/usb/gadget/function/uvc_queue.c > @@ -21,6 +21,7 @@ > #include <media/videobuf2-vmalloc.h> > > #include "uvc.h" > +#include "uvc_video.h" > > /* ------------------------------------------------------------------------ > * Video buffers queue management. > @@ -86,7 +87,7 @@ static int uvc_queue_setup(struct vb2_queue *vq, > } > > video->req_size = req_size; > - video->uvc_num_requests = nreq; > + video->uvc_num_requests = nreq * UVCG_STREAMING_MIN_BUFFERS; > > return 0; > } > diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c > index 392fb400aad14..f96074f2c2824 100644 > --- a/drivers/usb/gadget/function/uvc_v4l2.c > +++ b/drivers/usb/gadget/function/uvc_v4l2.c > @@ -357,6 +357,18 @@ static int uvc_v4l2_s_parm(struct file *file, void *fh, > return 0; > } > > +static int uvc_g_ctrl(struct file *file, void *priv, struct v4l2_control *vc) > +{ > + int ret = -EINVAL; > + > + if (vc->id == V4L2_CID_MIN_BUFFERS_FOR_OUTPUT) { > + vc->value = UVCG_STREAMING_MIN_BUFFERS; > + ret = 0; > + } > + > + return ret; > +} > + > static int > uvc_v4l2_enum_frameintervals(struct file *file, void *fh, > struct v4l2_frmivalenum *fival) > @@ -629,6 +641,7 @@ const struct v4l2_ioctl_ops uvc_v4l2_ioctl_ops = { > .vidioc_streamoff = uvc_v4l2_streamoff, > .vidioc_s_parm = uvc_v4l2_s_parm, > .vidioc_g_parm = uvc_v4l2_g_parm, > + .vidioc_g_ctrl = uvc_g_ctrl, > .vidioc_subscribe_event = uvc_v4l2_subscribe_event, > .vidioc_unsubscribe_event = uvc_v4l2_unsubscribe_event, > .vidioc_default = uvc_v4l2_ioctl_default,
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index f6bc58fb02b84..e0b1f78fdbc65 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -71,6 +71,8 @@ extern unsigned int uvc_gadget_trace_param; #define UVCG_REQUEST_HEADER_LEN 12 +#define UVCG_STREAMING_MIN_BUFFERS 4 + /* ------------------------------------------------------------------------ * Structures */ diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c index e33ce72325031..157e7f7d49c7a 100644 --- a/drivers/usb/gadget/function/uvc_queue.c +++ b/drivers/usb/gadget/function/uvc_queue.c @@ -21,6 +21,7 @@ #include <media/videobuf2-vmalloc.h> #include "uvc.h" +#include "uvc_video.h" /* ------------------------------------------------------------------------ * Video buffers queue management. @@ -86,7 +87,7 @@ static int uvc_queue_setup(struct vb2_queue *vq, } video->req_size = req_size; - video->uvc_num_requests = nreq; + video->uvc_num_requests = nreq * UVCG_STREAMING_MIN_BUFFERS; return 0; } diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c index 392fb400aad14..f96074f2c2824 100644 --- a/drivers/usb/gadget/function/uvc_v4l2.c +++ b/drivers/usb/gadget/function/uvc_v4l2.c @@ -357,6 +357,18 @@ static int uvc_v4l2_s_parm(struct file *file, void *fh, return 0; } +static int uvc_g_ctrl(struct file *file, void *priv, struct v4l2_control *vc) +{ + int ret = -EINVAL; + + if (vc->id == V4L2_CID_MIN_BUFFERS_FOR_OUTPUT) { + vc->value = UVCG_STREAMING_MIN_BUFFERS; + ret = 0; + } + + return ret; +} + static int uvc_v4l2_enum_frameintervals(struct file *file, void *fh, struct v4l2_frmivalenum *fival) @@ -629,6 +641,7 @@ const struct v4l2_ioctl_ops uvc_v4l2_ioctl_ops = { .vidioc_streamoff = uvc_v4l2_streamoff, .vidioc_s_parm = uvc_v4l2_s_parm, .vidioc_g_parm = uvc_v4l2_g_parm, + .vidioc_g_ctrl = uvc_g_ctrl, .vidioc_subscribe_event = uvc_v4l2_subscribe_event, .vidioc_unsubscribe_event = uvc_v4l2_unsubscribe_event, .vidioc_default = uvc_v4l2_ioctl_default,
We increase the minimum amount of v4l2 buffers that will be possibly enqueued into the hardware and allocate at least UVCG_STREAMING_MIN_BUFFERS amount of requests. This way the driver has also more requests available to prefill the isoc hardware with. Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> --- v3 -> v4: - v1 -> v3: new patch --- drivers/usb/gadget/function/uvc.h | 2 ++ drivers/usb/gadget/function/uvc_queue.c | 3 ++- drivers/usb/gadget/function/uvc_v4l2.c | 13 +++++++++++++ 3 files changed, 17 insertions(+), 1 deletion(-)