18.08.2021 07:31, Viresh Kumar пишет:

On 18-08-21, 07:12, Dmitry Osipenko wrote:

quoted

18.08.2021 06:55, Viresh Kumar пишет:

quoted

On 17-08-21, 18:49, Dmitry Osipenko wrote:

quoted

17.08.2021 10:55, Viresh Kumar пишет:
...

quoted

quoted

+int dev_pm_opp_sync(struct device *dev)
+{
+	struct opp_table *opp_table;
+	struct dev_pm_opp *opp;
+	int ret = 0;
+
+	/* Device may not have OPP table */
+	opp_table = _find_opp_table(dev);
+	if (IS_ERR(opp_table))
+		return 0;
+
+	if (!_get_opp_count(opp_table))
+		goto put_table;
+
+	opp = _find_current_opp(dev, opp_table);
+	ret = _set_opp(dev, opp_table, opp, opp->rate);

And I am not sure how this will end up working, since new OPP will be
equal to old one. Since I see you call this from resume() at many
places.

Initially OPP table is "uninitialized" and opp_table->enabled=false,
hence the first sync always works even if OPP is equal to old one. Once
OPP has been synced, all further syncs are NO-OPs, hence it doesn't
matter how many times syncing is called.

https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/opp/core.c#L1012

Right, but how will this work from Resume ? Won't that be a no-op ?

The first resume initializes the OPP state on sync, all further syncs on
resume are no-ops.

But the OPPs should already be initialized as someone must have called
opp-set-rate earlier ? Why do this from resume and not probe ?

This will set voltage level without having an actively used hardware.
Take a 3d driver for example, if you set the rate on probe and
rpm-resume will never be called, then the voltage will be set high,
while hardware is kept suspended if userspace will never wake it up by
executing a 3d job.