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UPSTREAM: usb: gadget: uvc: decrease the interrupt load to a quarter

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With usb3 we handle many more requests. Decrease the interrupt load by
only enabling the interrupt every quarter of the allocated requests.

Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>

--
v1 -> v2: - edited patch description
	  - removed extra parantheses
	  - added a comment for the logic
	  - using unsigned int instead of int
	  - reinitializing req_int_count in uvcg_video_enable
v2 -> v3: -
Link: https://lore.kernel.org/r/20210628155311.16762-6-m.grzeschik@pengutronix.de

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

(cherry picked from commit fc78941d8169cba40e420eb24a88789b0406c738)
Bug: 242344221
Bug: 325993121
Change-Id: I4b40c4bbd90b9b8ad85957a77589fb304e00a876
Signed-off-by: Avichal Rakesh <arakesh@google.com>
Signed-off-by: Luca Stefani <luca@osomprivacy.com>
This commit is contained in:
Michael Grzeschik 2021-06-28 17:53:11 +02:00 committed by Luca Stefani
parent ad31e24641
commit beecd97e3a
2 changed files with 18 additions and 0 deletions
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2
drivers/usb/gadget/function/uvc.h
View File

@ -100,6 +100,8 @@ struct uvc_video {
struct list_head req_free;
spinlock_t req_lock;
unsigned int req_int_count;
void (*encode) (struct usb_request *req, struct uvc_video *video,
struct uvc_buffer *buf);

16
drivers/usb/gadget/function/uvc_video.c
View File

@ -294,6 +294,19 @@ static void uvcg_video_pump(struct work_struct *work)
video->encode(req, video, buf);
/* With usb3 we have more requests. This will decrease the
* interrupt load to a quarter but also catches the corner
* cases, which needs to be handled */
if (list_empty(&video->req_free) ||
buf->state == UVC_BUF_STATE_DONE ||
!(video->req_int_count %
DIV_ROUND_UP(video->uvc_num_requests, 4))) {
video->req_int_count = 0;
req->no_interrupt = 0;
} else {
req->no_interrupt = 1;
}
/* Queue the USB request */
ret = uvcg_video_ep_queue(video, req);
spin_unlock_irqrestore(&queue->irqlock, flags);
@ -305,6 +318,7 @@ static void uvcg_video_pump(struct work_struct *work)
/* Endpoint now owns the request */
req = NULL;
video->req_int_count++;
}
if (!req)
@ -355,6 +369,8 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
} else
video->encode = uvc_video_encode_isoc;
video->req_int_count = 0;
schedule_work(&video->pump);
return ret;