4.14-stable review patch. If anyone has any objections, please let me know.
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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__);