[PATCH v4 10/10] usb: gadget: uvc: add min g_ctrl vidioc and set min buffs to 4

Michael Grzeschik
2024-08-13T09:34:30Z

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
+
/* ------------------------------------------------------------------------
* 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,

--
2.39.2