netdev - Re: calling request_firmware() from module init will not work with recent/future udev versions

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Message-ID: <4F3CF0C1.3090304@broadcom.com>
Date:	Thu, 16 Feb 2012 13:04:17 +0100
From:	"Arend van Spriel" <arend@...adcom.com>
To:	"Johannes Berg" <johannes@...solutions.net>
cc:	"Kay Sievers" <kay.sievers@...y.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
	"Tom Gundersen" <teg@...m.no>, "Andy Whitcroft" <apw@...onical.com>
Subject: Re: calling request_firmware() from module init will not work
 with recent/future udev versions

On 01/16/2012 09:57 AM, Johannes Berg wrote:
>> Now the problem, the pcidev event is blocking in modprobe and waits
>> >  for the child event it has generated to finish, but udev does not
>> >  start the event because the parent still blocks in modprobe ->
>> >  deadlock until default firmware timeout of 60 sec. What we want here,
>> >  for several reasons not only udev's dependency logic, is that modprobe
>> >  never waits for userspace transactions to finish.
> Ok, thanks for the description. I guess to me that means nothing really
> changes much in the situation I'm thinking of.

I am working on changes in brcm80211 driver and the behaviour changes 
slightly. The async firmware request basically kicks of a kernel thread 
to do the actual request. So the probe finishes successfully regardless 
what the results will be of the actual firmware request. Hence the 
driver is associated with the hardware.

>> >  If userspace is not responding, the firmware request times out after
>> >  60 seconds and the driver is not associated with any hardware. To
>> >  retry the firmware loading, the module needs to be unloaded and
>> >  reloaded, or the driver needs to be asked to bind to a device again by
>> >  writing to the 'bind' in file in the sysfs driver directory.
> Right.
>

If my previous statement is true, what does it mean regarding retrying 
the firmware loading?

Gr. AvS

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