linux-kernel - Re: Alternative approach to solve the deferred probe

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Message-ID: <20151021203519.GO32532@n2100.arm.linux.org.uk>
Date:	Wed, 21 Oct 2015 21:35:19 +0100
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Frank Rowand <frowand.list@...il.com>
Cc:	Geert Uytterhoeven <geert@...ux-m68k.org>,
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Subject: Re: Alternative approach to solve the deferred probe

On Wed, Oct 21, 2015 at 08:36:23AM -0700, Frank Rowand wrote:
> On 10/21/2015 1:18 AM, Russell King - ARM Linux wrote:
> > On Tue, Oct 20, 2015 at 08:58:19PM -0700, Frank Rowand wrote:
> >> On 10/20/2015 8:46 AM, Russell King - ARM Linux wrote:
> 
> < snip >
> 
> >>> +
> >>>  static bool driver_deferred_probe_enable = false;
> >>> +
> >>>  /**
> >>>   * driver_deferred_probe_trigger() - Kick off re-probing deferred devices
> >>>   *
> >>> @@ -188,6 +210,13 @@ static int deferred_probe_initcall(void)
> >>>  	driver_deferred_probe_trigger();
> >>
> >> Couldn't you put the "driver_deferred_probe_report = true" here?  And then
> >> not add another round of probes.
> > 
> > The idea is not to report anything for drivers that were deferred
> > during the normal bootup.  The above is part of the normal bootup,
> > and the deferred activity should not be warned about.
> 
> The above is currently the last point for probe to succeed or defer
> (until possibly, as you mentioned, module loading resolves the defer).
> If a probe defers above, it will defer again below.  The set of defers
> should be exactly the same above and below.

Why should it?  Isn't this late_initcall() the first opportunity that
deferred devices get to be re-probed from their first set of attempts
via the drivers having their initcalls called?

If what you're saying is true, what's the point of this late_initcall()?

<re-cut again, I've no idea why you keep adding it back>

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