Re: [GIT PULL] On-demand device probing

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, Oct 19, 2015 at 05:00:54PM +0200, Tomeu Vizoso wrote:
> On 19 October 2015 at 16:30, Russell King - ARM Linux
> <linux@xxxxxxxxxxxxxxxx> wrote:
> > I typically see one or two, maybe five maximum on the platforms I have
> > here, but normally zero.
> 
> Hmm, I have given a look at our lava farm and have seen 2 dozens as
> common (with multi_v7).

No, because the lava farms tend not to be public.

> > What you can do is print those devices which have failed to probe at
> > late_initcall() time - possibly augmenting that with reports from
> > subsystems showing what resources are not available, but that's only
> > a guide, because of the "it might or might not be in a kernel module"
> > problem.
> 
> Well, adding those reports would give you a changelog similar to the
> one in this series...

I'm not sure about that, because what I was thinking of is adding
a flag which would be set at late_initcall() time prior to running
a final round of deferred device probing.

This flag would then be used in a deferred_warn() printk function
which would normally be silent, but when this flag is set, it would
print the reason for the deferral - and this would replace (or be
added) to the subsystems and drivers which return -EPROBE_DEFER.

That has the effect of hiding all the deferrals up until just before
launching into userspace, which should then acomplish two things -
firstly, getting rid of the rather useless deferred messages up to
that point, and secondly printing the reason why the remaining
deferrals are happening.

That should be a small number of new lines plus a one-line change
in subsystems and drivers.

-- 
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux