Commit 6b37bd78 authored Jun 21, 2018 by Joshua Frkuska Committed by Felipe Balbi Jul 17, 2018

usb: gadget: u_audio: update hw_ptr in iso_complete after data copied



In u_audio_iso_complete, the runtime hw_ptr is updated before the
data is actually copied over to/from the buffer/dma area. When
ALSA uses this hw_ptr, the data may not actually be available to
be used. This causes trash/stale audio to play/record. This
patch updates the hw_ptr after the data has been copied to avoid
this.

Fixes: 132fcb46 ("usb: gadget: Add Audio Class 2.0 Driver")
Signed-off-by: Joshua Frkuska <joshua_frkuska@mentor.com>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

parent dfa042fa

drivers/usb/gadget/function/u_audio.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -143,7 +143,6 @@ static void u_audio_iso_complete(struct usb_ep ep, struct usb_request req)
		update_alsa = true;

		hw_ptr = prm->hw_ptr;
		prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes;

		spin_unlock_irqrestore(&prm->lock, flags);

		@@ -168,6 +167,11 @@ static void u_audio_iso_complete(struct usb_ep ep, struct usb_request req)
		}
		}

		spin_lock_irqsave(&prm->lock, flags);
		/* update hw_ptr after data is copied to memory */
		prm->hw_ptr = (hw_ptr + req->actual) % prm->dma_bytes;
		spin_unlock_irqrestore(&prm->lock, flags);

		exit:
		if (usb_ep_queue(ep, req, GFP_ATOMIC))
		dev_err(uac->card->dev, "%d Error!\n", __LINE__);