[alsa-devel] Applied "ASoC: SOF: force end-of-file for debugfs trace at suspend" to the asoc tree

[Mark Brown]

The patch

   ASoC: SOF: force end-of-file for debugfs trace at suspend

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.3

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From ec9025e5d3c5b5f2027fa74be6afdaad9908b546 Mon Sep 17 00:00:00 2001
From: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Date: Fri, 24 May 2019 14:23:06 -0500
Subject: [PATCH] ASoC: SOF: force end-of-file for debugfs trace at suspend

Current trace implementation gets out of sync when sof device
is put to suspend. The debugfs file handle is kept open, but
firmware will reset its state. After resume, debugfs client's
read offset will not be synchronized to firmware and this may
result in traces read in incorrect order and/or stale data being
read after resume.

Add logic to signal end-of-file to read() when firmware tracing
has ended, and all trace data has been read. This allows debugfs
client to capture all trace data, and reopen the trace file to
ensure proper synchronization with firmware after reopening
the node.

Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Signed-off-by: Mark Brown <broonie at kernel.org>
---
 sound/soc/sof/sof-priv.h |  2 ++
 sound/soc/sof/trace.c    | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/sound/soc/sof/sof-priv.h b/sound/soc/sof/sof-priv.h
index 1e85d6f9c5c3..01a6219c326b 100644
--- a/sound/soc/sof/sof-priv.h
+++ b/sound/soc/sof/sof-priv.h
@@ -417,6 +417,8 @@ struct snd_sof_dev {
 	u32 host_offset;
 	u32 dtrace_is_enabled;
 	u32 dtrace_error;
+	u32 dtrace_draining;
+
 	u32 msi_enabled;
 
 	void *private;			/* core does not touch this */
diff --git a/sound/soc/sof/trace.c b/sound/soc/sof/trace.c
index a2d89d295f0f..b02520f8e595 100644
--- a/sound/soc/sof/trace.c
+++ b/sound/soc/sof/trace.c
@@ -43,6 +43,15 @@ static size_t sof_wait_trace_avail(struct snd_sof_dev *sdev,
 	if (ret)
 		return ret;
 
+	if (!sdev->dtrace_is_enabled && sdev->dtrace_draining) {
+		/*
+		 * tracing has ended and all traces have been
+		 * read by client, return EOF
+		 */
+		sdev->dtrace_draining = false;
+		return 0;
+	}
+
 	/* wait for available trace data from FW */
 	init_waitqueue_entry(&wait, current);
 	set_current_state(TASK_INTERRUPTIBLE);
@@ -104,10 +113,23 @@ static ssize_t sof_dfsentry_trace_read(struct file *file, char __user *buffer,
 	return count;
 }
 
+static int sof_dfsentry_trace_release(struct inode *inode, struct file *file)
+{
+	struct snd_sof_dfsentry *dfse = inode->i_private;
+	struct snd_sof_dev *sdev = dfse->sdev;
+
+	/* avoid duplicate traces at next open */
+	if (!sdev->dtrace_is_enabled)
+		sdev->host_offset = 0;
+
+	return 0;
+}
+
 static const struct file_operations sof_dfs_trace_fops = {
 	.open = simple_open,
 	.read = sof_dfsentry_trace_read,
 	.llseek = default_llseek,
+	.release = sof_dfsentry_trace_release,
 };
 
 static int trace_debugfs_create(struct snd_sof_dev *sdev)
@@ -155,6 +177,7 @@ int snd_sof_init_trace_ipc(struct snd_sof_dev *sdev)
 	params.stream_tag = 0;
 
 	sdev->host_offset = 0;
+	sdev->dtrace_draining = false;
 
 	ret = snd_sof_dma_trace_init(sdev, &params.stream_tag);
 	if (ret < 0) {
@@ -291,6 +314,8 @@ void snd_sof_release_trace(struct snd_sof_dev *sdev)
 			"error: fail in snd_sof_dma_trace_release %d\n", ret);
 
 	sdev->dtrace_is_enabled = false;
+	sdev->dtrace_draining = true;
+	wake_up(&sdev->trace_sleep);
 }
 EXPORT_SYMBOL(snd_sof_release_trace);
 
-- 
2.20.1