On 11/14/22 04:29, Charles Keepax wrote:
> It is rather inefficient to be constantly enabling/disabling the PM
> runtime as we print out each individual register, switch to holding a PM
> runtime reference across the whole register output.
the change is good, but technically the pm_runtime resume happens for
the first read and suspend with a delay if use_autosuspend() is enabled,
so presumably we'll see the same number of resume/suspend with the
existing code and the suggested change.
Maybe update the commit message to mention that we constantly change
reference counts, as you did in the next patch?
>
> Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/soundwire/debugfs.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/soundwire/debugfs.c b/drivers/soundwire/debugfs.c
> index 49900cd207bc7..0718e9cda138a 100644
> --- a/drivers/soundwire/debugfs.c
> +++ b/drivers/soundwire/debugfs.c
> @@ -4,6 +4,7 @@
> #include <linux/device.h>
> #include <linux/debugfs.h>
> #include <linux/mod_devicetable.h>
> +#include <linux/pm_runtime.h>
> #include <linux/slab.h>
> #include <linux/soundwire/sdw.h>
> #include <linux/soundwire/sdw_registers.h>
> @@ -35,7 +36,7 @@ static ssize_t sdw_sprintf(struct sdw_slave *slave,
> {
> int value;
>
> - value = sdw_read(slave, reg);
> + value = sdw_read_no_pm(slave, reg);
>
> if (value < 0)
> return scnprintf(buf + pos, RD_BUF - pos, "%3x\tXX\n", reg);
> @@ -55,6 +56,10 @@ static int sdw_slave_reg_show(struct seq_file *s_file, void *data)
> if (!buf)
> return -ENOMEM;
>
> + ret = pm_runtime_resume_and_get(&slave->dev);
> + if (ret < 0 && ret != -EACCES)
> + return ret;
> +
> ret = scnprintf(buf, RD_BUF, "Register Value\n");
>
> /* DP0 non-banked registers */
> @@ -112,6 +117,10 @@ static int sdw_slave_reg_show(struct seq_file *s_file, void *data)
> }
>
> seq_printf(s_file, "%s", buf);
> +
> + pm_runtime_mark_last_busy(&slave->dev);
> + pm_runtime_put(&slave->dev);
> +
> kfree(buf);
>
> return 0;
