RE: [PATCH 1/4] firmware: arm_scmi: bus: Bypass setting fwnode for scmi cpufreq

Peng Fan
2025-03-11T08:38:12Z

> Subject: Re: [PATCH 1/4] firmware: arm_scmi: bus: Bypass setting
> fwnode for scmi cpufreq
>
> On Mon, Mar 10, 2025 at 11:59:33AM +0000, Sudeep Holla wrote:
> > On Mon, Mar 10, 2025 at 10:45:44AM +0000, Peng Fan wrote:
> > > > Subject: Re: [PATCH 1/4] firmware: arm_scmi: bus: Bypass setting
> > > > fwnode for scmi cpufreq
> > > >
> > > > On Thu, Feb 20, 2025 at 08:59:18AM +0800, Peng Fan wrote:
> > > > >
> > > > > Sorry, if I misunderstood.
> > > > >
> > > > > I will give a look on this and propose a RFC.
> > > > >
> > > > > DT maintainers may ask for a patchset including binding change
> > > > > and driver changes to get a whole view on the compatible stuff.
> > > > >
> > > > > BTW, Cristian, Saravana if you have any objections/ideas or
> > > > > would
> > > > take
> > > > > on this effort, please let me know.
> > > > >
> > > >
> > > > Can you point me to the DTS with which you are seeing this issue ?
> > > > I am trying to reproduce the issue but so far not successful. I
> > > > did move to power-domains for CPUFreq on Juno. IIUC all we
> need is
> > > > both cpufreq and performance genpd drivers in the kernel and
> then
> > > > GPU using perf genpd fails with probe deferral right ? I need
> > > > pointers to reproduce the issue so that I can check if what I have
> > > > cooked up as a solution really works.
> > >
> > > This is in downstream tree:
> > >
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2F
> gi
> > > thub.com%2Fnxp-imx%2Flinux-imx%2Fblob%2Flf-
> 6.6.y%2Farch%2Farm64%2Fbo
> > >
> ot%2Fdts%2Ffreescale%2Fimx95.dtsi%23L2971&data=05%7C02%7Cpe
> ng.fan%40
> > >
> nxp.com%7C72778d531e944c7214ca08dd5fd95012%7C686ea1d3bc2
> b4c6fa92cd99
> > >
> c5c301635%7C0%7C0%7C638772109152491267%7CUnknown%7CT
> WFpbGZsb3d8eyJFb
> > >
> XB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOI
> joiTWFpb
> > >
> CIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=nHFiE5qD7NpmdGmj
> SUL0mIdOq8P4W
> > > ErqVq8xE%2Fb3WM0%3D&reserved=0
> > >
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2F
> gi
> > > thub.com%2Fnxp-imx%2Flinux-imx%2Fblob%2Flf-
> 6.6.y%2Farch%2Farm64%2Fbo
> > >
> ot%2Fdts%2Ffreescale%2Fimx95.dtsi%23L3043&data=05%7C02%7Cpe
> ng.fan%40
> > >
> nxp.com%7C72778d531e944c7214ca08dd5fd95012%7C686ea1d3bc2
> b4c6fa92cd99
> > >
> c5c301635%7C0%7C0%7C638772109152521215%7CUnknown%7CT
> WFpbGZsb3d8eyJFb
> > >
> XB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOI
> joiTWFpb
> > >
> CIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=M4LJumL6y9bQ%2FL
> ocPvlNiMnCFtO
> > > vODYNrC0DGbbydxY%3D&reserved=0
> > >
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2F
> gi
> > > thub.com%2Fnxp-imx%2Flinux-imx%2Fblob%2Flf-
> 6.6.y%2Farch%2Farm64%2Fbo
> > >
> ot%2Fdts%2Ffreescale%2Fimx95.dtsi%23L80&data=05%7C02%7Cpeng
> .fan%40nx
> > >
> p.com%7C72778d531e944c7214ca08dd5fd95012%7C686ea1d3bc2b4
> c6fa92cd99c5
> > >
> c301635%7C0%7C0%7C638772109152541725%7CUnknown%7CTWF
> pbGZsb3d8eyJFbXB
> > >
> 0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoi
> TWFpbCI
> > >
> sIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=VpxcGrB6Dnr9yCO%2F
> wl8sEw1LYSlX5
> > > nPHqnlJ5mKm%2B7A%3D&reserved=0
> > >
> > > we are using "power-domains" property for cpu perf and gpu/vpu
> perf.
> > >
> > > If cpufreq.off=1 is set in bootargs, the vpu/gpu driver will defer
> probe.
> > >
> >
> > OK, does the probe of these drivers get called or they don't as the
> > driver core doesn't allow that ? I just have a dummy driver for mali
> > on Juno which just does dev_pm_domain_attach_list() in the probe
> and
> > it seem to succeed even when cpufreq.off=1 is passed. I see
> > scmi-cpufreq failing with -ENODEV as expected.
> >
> > I need to follow the code and check if I can somehow reproduce. Also
> > are you sure this is not with anything in the downstream code ? Also
> > have you tried this with v6.14-rc* ? Are you sure all the fw_devlink
> > code is backported in the tree you pointed me which is v6.6-stable ?
> >
>
> I even tried the above branch, but no luck. The above is neither latest
> stable version nor pure stable. It has few extra patches backported
> though IIUC. Anyways any pointers to enable me to reproduce the
> issue would be much appreciated.

I will setup test based latest linux-next and share results. Please wait.

Thanks,
Peng.
>
> --
> Regards,
> Sudeep