Date: Wed, 9 May 2007 14:37:35 +0200
From: Cornelia Huck <cornelia.huck@de.ibm.com>
To: Duncan Sands <duncan.sands@math.u-psud.fr>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Adrian Bunk <bunk@stusta.de>, Greg K-H <greg@kroah.com>,
       linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Please revert 5adc55da4a7758021bcc374904b0f8b076508a11
 (PCI_MULTITHREAD_PROBE)
Message-ID: <20070509143735.036351e4@gondolin.boeblingen.de.ibm.com>
In-Reply-To: <200705091116.06995.duncan.sands@math.u-psud.fr>
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	<20070509104541.48cc901e@gondolin.boeblingen.de.ibm.com>
	<200705091116.06995.duncan.sands@math.u-psud.fr>
Organization: IBM Deutschland Entwicklung GmbH
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On Wed, 9 May 2007 11:16:06 +0200,
Duncan Sands <duncan.sands@math.u-psud.fr> wrote:

> The main difficulties encountered with usbatm were: (1) avoiding race
> conditions on device disconnect; (2) providing a way to cancel heavy_init.
> As mentioned in my original email, heavy_init could run forever depending
> on how the system is configured.  In the current implementation a signal
> is sent on disconnect(), to indicate that the game is up, then disconnect()
> blocks until heavy_init terminates, if it hasn't already.  A better method
> would be to allow registration of a cancel() routine, which disconnect
> would call before blocking on heavy_init termination.  This could send a
> signal, or complete a completion, or whatever.

Yes, a cancel routine would make sense also in the generic
probe()/setup() case.

> Sadly, the generic firmware
> loading infrastructure doesn't have a way of asynchronously cancelling a
> firmware load, so right now cancellation only does something if the firmware
> has already been loaded from disk, in which case it cancels the upload to the
> modem (which is the most time consuming part).

Hm, a firmware load cancellation interface looks like a worthwile
addition to the firmware code (especially since fw_load_abort() already
exists and can even be triggered by userspace).
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