[PATCH v3 00/10] usb: gadget: uvc: effectively fill the udc isoc pipeline with available video buffers

[Michael Grzeschik]

This patch series is improving the size calculation and allocation of
the uvc requests. Using the selected frame duration of the stream it is
possible to calculate the number of requests based on the interval
length.

It also precalculates the request length based on the actual per frame
size for compressed formats.

For this calculations to work it was needed to rework the request
queueing by moving the encoding to one extra thread (in this case we
chose the qbuf) context.

Next it was needed to move the actual request enqueueing to one extra
thread which is kept busy to fill the isoc queue in the udc.

As a final step the series is increasing the minimum amount of
v4l2 buffers to 4 and allocates at least the amount of usb_requests
to store them in the usb gadgte isoc pipeline.

Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
---
Changes in v3:
- Added more patches necessary to properly rework the request queueing
- Link to v2: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v2-0-12690f7a2eff@xxxxxxxxxxxxxx

Changes in v2:
- added header size into calculation of request size
- Link to v1: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v1-0-9436c4716233@xxxxxxxxxxxxxx

---
Michael Grzeschik (10):
      usb: gadget: uvc: always set interrupt on zero length requests
      usb: gadget: uvc: only enqueue zero length requests in potential underrun
      usb: gadget: uvc: remove pump worker and enqueue all buffers per frame in qbuf
      usb: gadget: uvc: rework to enqueue in pump worker from encoded queue
      usb: gadget: uvc: remove uvc_video_ep_queue_initial_requests
      usb: gadget: uvc: set req_size once when the vb2 queue is calculated
      usb: gadget: uvc: add g_parm and s_parm for frame interval
      usb: gadget: uvc: set req_size and n_requests based on the frame interval
      usb: gadget: uvc: set req_length based on payload by nreqs instead of req_size
      usb: gadget: uvc: add min g_ctrl vidioc and set min buffs to 4

 drivers/usb/gadget/function/f_uvc.c     |   3 +-
 drivers/usb/gadget/function/uvc.h       |  14 +-
 drivers/usb/gadget/function/uvc_queue.c |  52 +++++--
 drivers/usb/gadget/function/uvc_queue.h |   1 +
 drivers/usb/gadget/function/uvc_v4l2.c  |  67 ++++++++-
 drivers/usb/gadget/function/uvc_video.c | 236 +++++++++++++-------------------
 drivers/usb/gadget/function/uvc_video.h |   1 +
 7 files changed, 215 insertions(+), 159 deletions(-)
---
base-commit: 1722389b0d863056d78287a120a1d6cadb8d4f7b
change-id: 20240403-uvc_request_length_by_interval-a7efd587d963

Best regards,
-- 
Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>