On Thu 2014-09-11 13:23:54, Dmitry Torokhov wrote:

On Thu, Sep 11, 2014 at 12:59:25PM -0700, James Bottomley wrote:

quoted

On Tue, 2014-09-09 at 16:01 -0700, Dmitry Torokhov wrote:

quoted

On Tuesday, September 09, 2014 03:46:23 PM James Bottomley wrote:

quoted

On Wed, 2014-09-10 at 07:41 +0900, Tejun Heo wrote:

quoted

The thing is that we have to have dynamic mechanism to listen for
device attachments no matter what and such mechanism has been in place
for a long time at this point.  The synchronous wait simply doesn't
serve any purpose anymore and kinda gets in the way in that it makes
it a possibly extremely slow process to tell whether loading of a
module succeeded or not because the wait for the initial round of
probe is piggybacked.

OK, so we just fire and forget in userland ... why bother inventing an
elaborate new infrastructure in the kernel to do exactly what

modprobe <mod> &

would do?

Just so we do not forget: we also want the no-modules case to also be able
to probe asynchronously so that a slow device does not stall kernel booting.

Yes, but we mostly do this anyway.  SCSI for instance does asynchronous
scanning of attached devices (once the cards are probed)

What would it do it card was a bit slow to probe?

quoted

but has a sync
point for ordering.

Quite often we do not really care about ordering of devices. I mean,
does it matter if your mouse is discovered before your keyboard or
after?

Actually yes, I suspect it does.

I do evtest /dev/input/eventX by hand, occassionaly. It would be
annoying if they moved between reboots.
									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html