| From foo@baz Sun Aug 26 09:13:00 CEST 2018 |
| From: Joshua Frkuska <joshua_frkuska@mentor.com> |
| Date: Thu, 21 Jun 2018 17:22:48 +0200 |
| Subject: usb: gadget: u_audio: update hw_ptr in iso_complete after data copied |
| |
| From: Joshua Frkuska <joshua_frkuska@mentor.com> |
| |
| [ Upstream commit 6b37bd78d30c890e575a1bda22978d1d2a233362 ] |
| |
| 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> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/usb/gadget/function/u_audio.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/usb/gadget/function/u_audio.c |
| +++ b/drivers/usb/gadget/function/u_audio.c |
| @@ -152,7 +152,6 @@ static void u_audio_iso_complete(struct |
| 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); |
| |
| @@ -177,6 +176,11 @@ static void u_audio_iso_complete(struct |
| } |
| } |
| |
| + 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__); |
