[PATCH 2/2] drm/panfrost: add devfreq regulator support

[Clément Péron]

On Sat, 9 May 2020 at 18:28, Clément Péron <peron.clem at gmail.com> wrote:
>
> Hi Steven,
>
> On Thu, 7 May 2020 at 16:30, Steven Price <steven.price at arm.com> wrote:
> >
> > On 02/05/2020 23:07, Clément Péron wrote:
> > > Hi Steven,
> > >
> > > On Tue, 14 Apr 2020 at 15:10, Steven Price <steven.price at arm.com> wrote:
> > >>
> > >> Hi Clément,
> > >>
> > >> On 13/04/2020 18:28, Clément Péron wrote:
> > >>> Hi Steven,
> > >>>
> > >
> <snip>
> >
> > Since you've got a reproduction - can you get a backtrace where the
> > regulator is getting disabled?
>
> Regulator is disabled from regulator_late_cleanup()
>
> [   33.757650] vdd-gpu: disabling
> [   33.760718] CPU: 2 PID: 31 Comm: kworker/2:1 Not tainted
> 5.7.0-rc2-next-20200424 #8
> [   33.768362] Hardware name: Beelink GS1 (DT)
> [   33.772553] Workqueue: events regulator_init_complete_work_function
> [   33.778813] Call trace:
> [   33.781261]  dump_backtrace+0x0/0x1a0
> [   33.784922]  show_stack+0x18/0x30
> [   33.788238]  dump_stack+0xc0/0x114
> [   33.791638]  regulator_late_cleanup+0x164/0x1f0
> [   33.796165]  class_for_each_device+0x64/0xe0
> [   33.800431]  regulator_init_complete_work_function+0x4c/0x60
> [   33.806084]  process_one_work+0x19c/0x330
> [   33.810090]  worker_thread+0x4c/0x430
> [   33.813748]  kthread+0x138/0x160
> [   33.816973]  ret_from_fork+0x10/0x24
>
> the use_count is at 0...
>
> I have check and the regulator_get is called and regulator_put is
> never called for vdd-gpu.
> Not sure what is happening here...

Looks like the OPP framework only get the regulator but never enable it...

I will send a question to OPP Maintainer about this.

Regards,
CLement

>
>
> >
> > >   - The Cooling map is not probe correctly :
> > > [    2.545756] panfrost 1800000.gpu: [drm:panfrost_devfreq_init
> > > [panfrost]] Failed to register cooling device
> > > Introduce in this commit :
> > > https://github.com/clementperon/linux/commit/0252c38fd55ad78366ac4b1714e285c88db34557
> > >
> > > Do you have an hint about what I'm missing ?
> >
> > Sorry, my knowledge of the cooling framework is very limited. What
> > you've got looks plausible, but I'm afraid I can't really help beyond
> > that! As before - can you try adding some printk()s in e.g.
> > of_devfreq_cooling_register_power() and find out where it is bailing out?
>
> Dumb issue, I was missing the CONFIG_DEVFREQ_THERMAL -_-, I will make
> a patch to enable it in arm64 defconfig.
>
> Regards,
> Clement
>
> >
> > Steve