Messages in this thread | | | Subject | Re: [PATCH v3 1/4] usb: gadget: f_midi: free usb request when done | From | Clemens Ladisch <> | Date | Fri, 9 Oct 2015 11:23:37 +0200 |
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Felipe Tonello wrote: > req->actual == req->length means that there is no data left to enqueue,
This condition is not checked in the patch.
> so free the request. > > Signed-off-by: Felipe F. Tonello <eu@felipetonello.com> > --- > drivers/usb/gadget/function/f_midi.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c > index edb84ca..93212ca 100644 > --- a/drivers/usb/gadget/function/f_midi.c > +++ b/drivers/usb/gadget/function/f_midi.c > @@ -256,9 +256,8 @@ f_midi_complete(struct usb_ep *ep, struct usb_request *req) > /* We received stuff. req is queued again, below */ > f_midi_handle_out_data(ep, req); > } else if (ep == midi->in_ep) { > - /* Our transmit completed. See if there's more to go. > - * f_midi_transmit eats req, don't queue it again. */ > - f_midi_transmit(midi, req); > + /* Our transmit completed. Don't queue it again. */ > + free_ep_req(ep, req); > return; > } > break;
The ALSA framework will give you a notification _once_. If the resulting data is larger than midi->buflen, then you have to continue sending packets. This is exactly what the call to f_midi_transmit() does.
(To decrease latency, it might be a good idea to queue multiple requests, but you wouldn't want to continue piling up requests if the host isn't listening. sound/usb/midi.c just allocates a fixed number of requests, and always reuses them.)
Regards, Clemens
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