Re: [PATCH v2 1/9] PM: domains: Delete usage of driver_deferred_probe_check_state()

[Saravana Kannan <saravanak@google.com>]

On Fri, Jul 1, 2022 at 8:08 AM Sudeep Holla <sudeep.holla@arm.com> wrote:
>
> Hi, Saravana,
>
> On Fri, Jul 01, 2022 at 01:26:12AM -0700, Saravana Kannan wrote:
>
> [...]
>
> > Can you check if this hack helps? If so, then I can think about
> > whether we can pick it up without breaking everything else. Copy-paste
> > tab mess up warning.
>
> Sorry for jumping in late and not even sure if this is right thread.
> I have not bisected anything yet, but I am seeing issues on my Juno R2
> with SCMI enabled power domains and Coresight AMBA devices.
>
> OF: amba_device_add() failed (-19) for /etf@20010000
> OF: amba_device_add() failed (-19) for /tpiu@20030000
> OF: amba_device_add() failed (-19) for /funnel@20040000
> OF: amba_device_add() failed (-19) for /etr@20070000
> OF: amba_device_add() failed (-19) for /stm@20100000
> OF: amba_device_add() failed (-19) for /replicator@20120000
> OF: amba_device_add() failed (-19) for /cpu-debug@22010000
> OF: amba_device_add() failed (-19) for /etm@22040000
> OF: amba_device_add() failed (-19) for /cti@22020000
> OF: amba_device_add() failed (-19) for /funnel@220c0000
> OF: amba_device_add() failed (-19) for /cpu-debug@22110000
> OF: amba_device_add() failed (-19) for /etm@22140000
> OF: amba_device_add() failed (-19) for /cti@22120000
> OF: amba_device_add() failed (-19) for /cpu-debug@23010000
> OF: amba_device_add() failed (-19) for /etm@23040000
> OF: amba_device_add() failed (-19) for /cti@23020000
> OF: amba_device_add() failed (-19) for /funnel@230c0000
> OF: amba_device_add() failed (-19) for /cpu-debug@23110000
> OF: amba_device_add() failed (-19) for /etm@23140000
> OF: amba_device_add() failed (-19) for /cti@23120000
> OF: amba_device_add() failed (-19) for /cpu-debug@23210000
> OF: amba_device_add() failed (-19) for /etm@23240000
> OF: amba_device_add() failed (-19) for /cti@23220000
> OF: amba_device_add() failed (-19) for /cpu-debug@23310000
> OF: amba_device_add() failed (-19) for /etm@23340000
> OF: amba_device_add() failed (-19) for /cti@23320000
> OF: amba_device_add() failed (-19) for /cti@20020000
> OF: amba_device_add() failed (-19) for /cti@20110000
> OF: amba_device_add() failed (-19) for /funnel@20130000
> OF: amba_device_add() failed (-19) for /etf@20140000
> OF: amba_device_add() failed (-19) for /funnel@20150000
> OF: amba_device_add() failed (-19) for /cti@20160000
>
> These are working fine with deferred probe in the mainline.
> I tried the hack you have suggested here(rather Tony's version),

Thanks for trying that.

> also
> tried with fw_devlink=0 and fw_devlink=1

0 and 1 aren't valid input to fw_devlink. But yeah, I don't expect
disabling it to make anything better.

> && fw_devlink.strict=0
> No change in the behaviour.
>
> The DTS are in arch/arm64/boot/dts/arm/juno-*-scmi.dts and there
> coresight devices are mostly in juno-cs-r1r2.dtsi

Thanks

> Let me know if there is anything obvious or you want me to bisect which
> means I need more time. I can do that next week.

I'll let you know once I poke at the DTS. We need to figure out why
fw_devlink wasn't blocking these from getting to the error (same as in
Tony's case). But since these are amba devices, I think I have some
guesses.

This is an old series that had some issues in some cases and I haven't
gotten around to looking at it. You can give that a shot if you can
apply it to a recent tree.
https://lore.kernel.org/lkml/20210304195101.3843496-1-saravanak@google.com/

After looking at that old patch again, I think I know what's going on.
For normal devices, the pm domain attach happens AFTER the device is
added and fw_devlink has had a chance to set up device links. And if
the suppliers aren't ready, really_probe() won't get as far as
dev_pm_domain_attach(). But for amba, the clock and pm domain
suppliers are "grabbed" before adding the device.

So with that old patch + always returning -EPROBE_DEFER in
amba_device_add() if amba_read_periphid() fails should fix your issue.

-Saravana