Hi Daniel,
On Thu, Aug 30, 2018 at 10:09 AM Daniel Lezcano
<daniel.lezc...@linaro.org> wrote:
> On 30/08/2018 09:54, Geert Uytterhoeven wrote:
> > On Wed, Aug 29, 2018 at 6:26 PM Daniel Lezcano
> > <daniel.lezc...@linaro.org> wrote:
> >> On 29/08/2018 17:44, Chris Brandt wrote:
> >>> On Wednesday, August 29, 2018 1, Daniel Lezcano wrote:
> >>>> Can the boot constraints [1] solve this issue instead of the changes you
> >>>> are proposing ?
> >>>>
> >>>> [1] https://lwn.net/Articles/747250/
> >>>
> >>> Thanks for the suggestion, but...
> >>>
> >>> I grepped for "boot_constraint" and it shows up nowhere in the current
> >>> kernel.
> >>>
> >>> Also, this article was written Feb 16, 2018, and I can see that the
> >>> patch series was still being submitted (V7) as of Feb 23, 2018.
> >>
> >> Ah ok, fair enough, I thought it was merged. In any case, after thinking
> >> about it, it wouldn't have helped.
> >>
> >> My concern is if we can avoid changing the TIMER_OF_DECLARE because of
> >> the boot order, it would be better.
> >>
> >> Can returning EPROBE_DEFER fix this issue? Or use the 'complex
> >> dependencies' [1]?
> >
> > *_OF_DECLARE() is not compatible with EPROBE_DEFER, which causes
> > issues with complex dependencies.
>
> What causes issues ? Add support for EPROBE_DEFER with OF_DECLARE or not
> having support of it ?
Driver init functions declared using *_OF_DECLARE() are called exactly once.
Hence if they fail, they are never retried. Calling order among subsystems is
hardcoded, and the actual order was determined by historical reasons (legacy
PC systems with always-on clocks and power domains ;-).
This breaks as soon as e.g. timers or interrupt controllers start depending
on clocks and/or power domains.
Drivers using the device driver framework are retried later when their init
function returns -EPROBE_DEFER. So (eventually) they all succeed
initialization.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
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
