Message-ID: <4F11E1CE.2050008@lwfinger.net> (sfid-20120114_211311_718026_CB9E6833)
Date: Sat, 14 Jan 2012 14:13:02 -0600
From: Larry Finger <Larry.Finger@lwfinger.net>
MIME-Version: 1.0
To: Arend van Spriel <arend@broadcom.com>
CC: "John W. Linville" <linville@tuxdriver.com>,
	Kay Sievers <kay.sievers@vrfy.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
	Tom Gundersen <teg@jklm.no>,
	Andy Whitcroft <apw@canonical.com>,
	Johannes Berg <johannes@sipsolutions.net>
Subject: Re: calling request_firmware() from module init will not work with
 recent/future udev versions
References: <CAPXgP11iT9K2KcDCJvw_druf5qdNjs0jLfrbpS7CcYh5vXrz_w@mail.gmail.com> <20120114175837.GA8504@tuxdriver.com> <4F11C75F.9030105@lwfinger.net> <4F11DEB8.7010708@broadcom.com>
In-Reply-To: <4F11DEB8.7010708@broadcom.com>
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Sender: linux-wireless-owner@vger.kernel.org

On 01/14/2012 01:59 PM, Arend van Spriel wrote:
> On 01/14/2012 07:20 PM, Larry Finger wrote:
>> On 01/14/2012 11:58 AM, John W. Linville wrote:
>>> Kay, thanks for the reports.  Drivers should definitely be loading
>>> firmware at IFF_UP time.
>>
>> As the maintainer for several drivers with this problem, I need to make some
>> changes. What call from mac80211 corresponds to IFF_UP?
>
> Hi, Larry
>
> The mac80211 start callback describes following:
>
>   * @start: Called before the first netdevice attached to the hardware
>   *	is enabled. This should turn on the hardware and must turn on
>   *	frame reception (for possibly enabled monitor interfaces.)
>   *	Returns negative error codes, these may be seen in userspace,
>   *	or zero.
>   *	When the device is started it should not have a MAC address
>   *	to avoid acknowledging frames before a non-monitor device
>   *	is added.
>   *	Must be implemented and can sleep.
>
> Seems to me a good place to do the firmware loading although it is not
> really IFF_UP.
>
>> I have looked into using asynchronous firmware loading, but I have not yet found
>> a good implementation.
>>
>> Larry
>
> In brcmsmac we request the firmware in the probe function so not in
> module_init, but I guess upon driver registration in the module_init the
> probe is called.

Thanks.

The rtlwifi drivers also load the firmware in the probe function, but do so 
synchronously, which is where they get in trouble with the new udev.

I'm planning on converting to asynchronous firmware loading with a check in the 
start routine.

Larry