On 5/17/23 11:37, Krzysztof Kozlowski wrote:
This reverts commit 57ed510b0547 ("soundwire: qcom: use pm_runtime_resume_and_get()") which introduced unbalanced pm_runtime_put(), when device did not have runtime PM enabled.
If pm_runtime_resume_and_get() failed with -EACCES, the driver continued execution and finally called pm_runtime_put_autosuspend(). Since pm_runtime_resume_and_get() drops the usage counter on every error, this lead to double decrement of that counter visible in certain debugfs actions on unattached devices (still in reset state):
$ cat /sys/kernel/debug/soundwire/master-0-0/sdw:0:0217:f001:00:0/registers qcom-soundwire 3210000.soundwire-controller: swrm_wait_for_wr_fifo_avail err write overflow soundwire sdw-master-0: trf on Slave 1 failed:-5 read addr e36 count 1 soundwire sdw:0:0217:f001:00:0: Runtime PM usage count underflow!
Fixes: 57ed510b0547 ("soundwire: qcom: use pm_runtime_resume_and_get()") Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org
Yes, this resume_and_get() added more problems indeed. One of those well-intended changes that went sideways.
Reviewed-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com
drivers/soundwire/qcom.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c index aad5942e5980..f442280af9d3 100644 --- a/drivers/soundwire/qcom.c +++ b/drivers/soundwire/qcom.c @@ -614,11 +614,12 @@ static irqreturn_t qcom_swrm_wake_irq_handler(int irq, void *dev_id) struct qcom_swrm_ctrl *ctrl = dev_id; int ret;
- ret = pm_runtime_resume_and_get(ctrl->dev);
- ret = pm_runtime_get_sync(ctrl->dev); if (ret < 0 && ret != -EACCES) { dev_err_ratelimited(ctrl->dev,
"pm_runtime_resume_and_get failed in %s, ret %d\n",
"pm_runtime_get_sync failed in %s, ret %d\n", __func__, ret);pm_runtime_put_noidle(ctrl->dev);@@ -1197,11 +1198,12 @@ static int qcom_swrm_startup(struct snd_pcm_substream *substream, struct snd_soc_dai *codec_dai; int ret, i;
- ret = pm_runtime_resume_and_get(ctrl->dev);
- ret = pm_runtime_get_sync(ctrl->dev); if (ret < 0 && ret != -EACCES) { dev_err_ratelimited(ctrl->dev,
"pm_runtime_resume_and_get failed in %s, ret %d\n",
"pm_runtime_get_sync failed in %s, ret %d\n", __func__, ret);pm_runtime_put_noidle(ctrl->dev);@@ -1402,11 +1404,12 @@ static int swrm_reg_show(struct seq_file *s_file, void *data) struct qcom_swrm_ctrl *ctrl = s_file->private; int reg, reg_val, ret;
- ret = pm_runtime_resume_and_get(ctrl->dev);
- ret = pm_runtime_get_sync(ctrl->dev); if (ret < 0 && ret != -EACCES) { dev_err_ratelimited(ctrl->dev,
"pm_runtime_resume_and_get failed in %s, ret %d\n",
"pm_runtime_get_sync failed in %s, ret %d\n", __func__, ret);pm_runtime_put_noidle(ctrl->dev);