From patchwork Thu Dec 5 17:35:15 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 297299 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 407A62C009F for ; Fri, 6 Dec 2013 04:40:18 +1100 (EST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1VocuK-0003HK-JI; Thu, 05 Dec 2013 17:40:12 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1VocrJ-0001cS-9u for kernel-team@lists.ubuntu.com; Thu, 05 Dec 2013 17:37:05 +0000 Received: from bl20-223-32.dsl.telepac.pt ([2.81.223.32] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1VocrI-000261-VC; Thu, 05 Dec 2013 17:37:05 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.5 33/90] ASoC: fsl: imx-pcm-fiq: omit fiq counter to avoid harm in unbalanced situations Date: Thu, 5 Dec 2013 17:35:15 +0000 Message-Id: <1386264972-5399-34-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1386264972-5399-1-git-send-email-luis.henriques@canonical.com> References: <1386264972-5399-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Cc: Oskar Schirmer , Mark Brown X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.5.7.27 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Oskar Schirmer commit fc7dc61d9a87011aaf8a6eb3144ebf9552adf5d2 upstream. Unbalanced calls to snd_imx_pcm_trigger() may result in endless FIQ activity and thus provoke eternal sound. While on the first glance, the switch statement looks pretty symmetric, the SUSPEND/RESUME pair is not: the suspend case comes along snd_pcm_suspend_all(), which for fsl/imx-pcm-fiq is called only at snd_soc_suspend(), but the resume case originates straight from the SNDRV_PCM_IOCTL_RESUME. This way userland may provoke an unbalanced resume, which might cause the fiq_enable counter to increase and never return to zero again, so eventually imx_pcm_fiq is never disabled. Simply removing the fiq_enable will solve the problem, as long as one never goes play and capture game simultaneously, but beware trying both at once, the early TRIGGER_STOP will cut off the other activity prematurely. So now playing and capturing is scrutinized separately, instead of by counting. Signed-off-by: Oskar Schirmer Signed-off-by: Mark Brown Signed-off-by: Luis Henriques --- sound/soc/fsl/imx-pcm-fiq.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) diff --git a/sound/soc/fsl/imx-pcm-fiq.c b/sound/soc/fsl/imx-pcm-fiq.c index 456b7d7..b18279d 100644 --- a/sound/soc/fsl/imx-pcm-fiq.c +++ b/sound/soc/fsl/imx-pcm-fiq.c @@ -42,7 +42,8 @@ struct imx_pcm_runtime_data { struct hrtimer hrt; int poll_time_ns; struct snd_pcm_substream *substream; - atomic_t running; + atomic_t playing; + atomic_t capturing; }; static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt) @@ -54,7 +55,7 @@ static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt) struct pt_regs regs; unsigned long delta; - if (!atomic_read(&iprtd->running)) + if (!atomic_read(&iprtd->playing) && !atomic_read(&iprtd->capturing)) return HRTIMER_NORESTART; get_fiq_regs(®s); @@ -122,7 +123,6 @@ static int snd_imx_pcm_prepare(struct snd_pcm_substream *substream) return 0; } -static int fiq_enable; static int imx_pcm_fiq; static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd) @@ -134,23 +134,27 @@ static int snd_imx_pcm_trigger(struct snd_pcm_substream *substream, int cmd) case SNDRV_PCM_TRIGGER_START: case SNDRV_PCM_TRIGGER_RESUME: case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: - atomic_set(&iprtd->running, 1); + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + atomic_set(&iprtd->playing, 1); + else + atomic_set(&iprtd->capturing, 1); hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns), HRTIMER_MODE_REL); - if (++fiq_enable == 1) - enable_fiq(imx_pcm_fiq); - + enable_fiq(imx_pcm_fiq); break; case SNDRV_PCM_TRIGGER_STOP: case SNDRV_PCM_TRIGGER_SUSPEND: case SNDRV_PCM_TRIGGER_PAUSE_PUSH: - atomic_set(&iprtd->running, 0); - - if (--fiq_enable == 0) + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) + atomic_set(&iprtd->playing, 0); + else + atomic_set(&iprtd->capturing, 0); + if (!atomic_read(&iprtd->playing) && + !atomic_read(&iprtd->capturing)) disable_fiq(imx_pcm_fiq); - break; + default: return -EINVAL; } @@ -198,7 +202,8 @@ static int snd_imx_open(struct snd_pcm_substream *substream) iprtd->substream = substream; - atomic_set(&iprtd->running, 0); + atomic_set(&iprtd->playing, 0); + atomic_set(&iprtd->capturing, 0); hrtimer_init(&iprtd->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL); iprtd->hrt.function = snd_hrtimer_callback;