Re: [GIT PULL] On-demand device probing

[Geert Uytterhoeven]

Hi Rafael,

On Wed, Oct 21, 2015 at 1:34 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> On Tuesday, October 20, 2015 09:15:01 AM Rob Herring wrote:
>> On Tue, Oct 20, 2015 at 2:56 AM, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
>> > ACPI uses platform devices too.  In fact, ACPI device objects are enumerated as
>> > platform devices by default now.
>>
>> Okay, I should have grepped for that:
>> drivers/base/platform.c:                ACPI_COMPANION_SET(&pdev->dev, NULL);
>> drivers/base/platform.c:        len = acpi_device_modalias(dev, buf,
>> PAGE_SIZE -1);
>> drivers/base/platform.c:        rc = acpi_device_uevent_modalias(dev, env);
>> drivers/base/platform.c:        /* Then try ACPI style match */
>> drivers/base/platform.c:        if (acpi_driver_match_device(dev, drv))
>>
>> These are all cases which have DT version as well, so we're not really
>> all that different here. There's a few more for DT, but that probably
>> means you have just not hit the problems we have yet. For example,
>> what happens if you have an interrupt line in which the controller is
>> probed after the device connected to the interrupt line? That required
>> resolving irqs in platform_get_irq rather than using static resources
>> to support deferred probe.
>
> We don't have this particular problem, because the IRQ controllers are
> enumerated in a special way.

What does "in a special way" mean? Can you please be more specific?

Can you have interrupt controllers that depend on clocks, pin controllers,
and PM domains?

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
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