[3/7] usb: gadget: u_audio: update hw_ptr in iso_complete after data copied
From: Eugeniu Rosca <hidden>
Date: 2018-06-21 15:22:48
Subsystem:
the rest, usb subsystem · Maintainers:
Linus Torvalds, Greg Kroah-Hartman
From: Joshua Frkuska <redacted>
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 <redacted>
Signed-off-by: Eugeniu Rosca <redacted>
---
drivers/usb/gadget/function/u_audio.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/function/u_audio.c b/drivers/usb/gadget/function/u_audio.c
index c0a65e110fc9..4c6df7130891 100644
--- a/drivers/usb/gadget/function/u_audio.c
+++ b/drivers/usb/gadget/function/u_audio.c@@ -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__);