From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51226 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730746AbeKLFsd (ORCPT ); Mon, 12 Nov 2018 00:48:33 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Joshua Frkuska" , "Felipe Balbi" , "Eugeniu Rosca" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: Subject: [PATCH 3.16 264/366] usb: gadget: u_audio: update hw_ptr in iso_complete after data copied In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: 3.16.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Joshua Frkuska 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 Signed-off-by: Eugeniu Rosca Signed-off-by: Felipe Balbi [bwh: Backported to 3.16: - Don't use a local hw_ptr variable - Adjust filename] Signed-off-by: Ben Hutchings --- --- 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__);