3.16.61-rc1 review patch. If anyone has any objections, please let me know.
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From: Joshua Frkuska joshua_frkuska@mentor.com
commit 6b37bd78d30c890e575a1bda22978d1d2a233362 upstream.
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: 132fcb460839 ("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 [bwh: Backported to 3.16: - Don't use a local hw_ptr variable - Adjust filename] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/drivers/usb/gadget/f_uac2.c +++ b/drivers/usb/gadget/f_uac2.c @@ -229,12 +229,16 @@ agdev_iso_complete(struct usb_ep *ep, st if (pending >= prm->period_size) update_alsa = true;
- prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes; - spin_unlock_irqrestore(&prm->lock, flags);
/* Pack USB load in ALSA ring buffer */ memcpy(dst, src, req->actual); + + spin_lock_irqsave(&prm->lock, flags); + /* update hw_ptr after data is copied to memory */ + prm->hw_ptr = (prm->hw_ptr + req->actual) % prm->dma_bytes; + spin_unlock_irqrestore(&prm->lock, flags); + exit: if (usb_ep_queue(ep, req, GFP_ATOMIC)) dev_err(&uac2->pdev.dev, "%d Error!\n", __LINE__);