On Tue, 7 Sept 2021 at 12:52, Geert Uytterhoeven [off-list ref] wrote:

Hi Ulf,

On Tue, Sep 7, 2021 at 12:36 PM Ulf Hansson [off-list ref] wrote:

quoted

On Fri, 3 Sept 2021 at 16:29, Geert Uytterhoeven [off-list ref] wrote:

quoted

On Fri, Sep 3, 2021 at 11:19 AM Ulf Hansson [off-list ref] wrote:

quoted

On Fri, 3 Sept 2021 at 01:04, Saravana Kannan [off-list ref] wrote:

quoted

fw_devlink could end up creating device links for bus only devices.
However, bus only devices don't get probed and can block probe() or
sync_state() [1] call backs of other devices. To avoid this, set up
these devices to get probed by the simple-pm-bus.

[1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ (local)
Signed-off-by: Saravana Kannan <redacted>
Tested-by: Saravana Kannan <redacted>

Again, this looks like a nice solution to the problem.

One question though. The Kconfig SIMPLE_PM_BUS, should probably be
"default y" - or something along those lines to make sure fw_devlink
works as expected.

I would love for SIMPLE_PM_BUS to go away, and all of its functionality
to be usurped by the standard simple-bus handling.

In the modern world, everything uses power management and Runtime
PM, and the distinction between "simple-bus" and "simple-pm-bus"
is purely artificial.

I think it's not that easy, but maybe I am wrong.

Today we have an opt-in way of supporting runtime PM (and power
management). In most cases it's up to drivers or subsystem level code
to decide if runtime PM should be enabled for the device.

Would it really be okay to enable runtime PM for all of them?

You're talking about the software policy side.

From my PoV, the issue is that this decision is leaked into DT, through
the different compatible values ("simple-pm-bus" vs. "simple-bus").

Yes, I do agree with you there.

On the other hand, it's probably not the only place where it's used as
"software configuration", so I don't have a big issue with it.

Kind regards
Uffe