Re: [PATCH 3/6] ARM: PSCI: Register with kernel restart handler

[Geert Uytterhoeven]

On Wed, Apr 13, 2016 at 3:10 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> On 04/13/2016 04:05 AM, Mark Rutland wrote:
>> On Fri, Apr 08, 2016 at 05:53:56AM -0700, Guenter Roeck wrote:
>>>
>>> Register with kernel restart handler instead of setting arm_pm_restart
>>> directly. This enables support for replacing the PSCI restart handler
>>> with a different handler if necessary for a specific board.
>>>
>>> Select a priority of 129 to indicate a higher than default priority, but
>>> keep it as low as possible since PSCI reset is known to fail on some
>>> boards.
>>
>> For reference, which boards?
>>
> Salvator-X, reported by Geert Uytterhoeven. Wolfram Sang also reported
> that it is broken on a board he is using, but I don't recall if it is
> the same board.

Yes it is.

>> It's unfortunate that that a PSCI 0.2+ implementation would be lacking a
>> working SYSTEM_RESET implementation, and it's certainly a mistake to
>> discourage.
>>
>>> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>>> ---
>>> It might make sense to introduce a restart-priority property for
>>> devicetree
>>> based configurations, but I am not sure if this would be acceptable.
>>
>>> From the DT side, I'm not keen on properties for priorities. They're
>> incredibly fragile and don't really encode a HW property.
>>
> Depends. It is a convenient means to say "primary restart method" or
> "may be broken".

The issue is supposed to be fixed in a more recent firmware, which I still have
to try.

DT indeed isn't the right place to work around this. What we need is a
blacklist of bad firmware versions...
Or Perfect Firmware from Day One on (like Perfect DT from Day One ;-)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds