linux-kernel - Re: [GIT *] Allow request_firmware() to be satisfied from in-kernel, use it in more drivers.

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Message-Id: <1216149637.27242.65.camel@violet.holtmann.net>
Date:	Tue, 15 Jul 2008 21:20:37 +0200
From:	Marcel Holtmann <marcel@...tmann.org>
To:	Frans Pop <elendil@...net.nl>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>, jeff@...zik.org,
	arjan@...radead.org, akpm@...ux-foundation.org,
	dwmw2@...radead.org, alan@...rguk.ukuu.org.uk,
	linux-kernel@...r.kernel.org
Subject: Re: [GIT *] Allow request_firmware() to be satisfied from
	in-kernel, use it in more drivers.

Hi Frans,

> > On Mon, 14 Jul 2008, Jeff Garzik wrote:
> >> IMO the newly added /inability/ to build firmware into kernel modules
> >> is a clear regression.
> > 
> > IMO you're being stupid.
> > 
> > How about explainign why it makes any difference what-so-ever?
> > 
> > If you can load the module, you can load the firmware. Claiming anything
> > else is just _stupid_.
> 
> Sure, in theory it's that simple. Here's a concrete example that shows how 
> things are harder in practice.
> 
> I use the 'make deb-pkg' target (from scripts/package) to build my Debian 
> kernel packages from git. So that needs to be adapted to include
> /lib/firmware. No real problem so far.
> 
> So then I build 2.6.27-rc1 and install it. Great.
> 
> You release 2.6.27-rc2 and I build it. Ouch! It fails to install, at least 
> if I want to install it _alongside_ 2.6.27-rc1 or other kernels (which I 
> do!). Why does it fail? Because dpkg's package management does not allow 
> one package to overwrite files already "owned" by another package.
> 
> So, how is this solved by Debian for already existing firmware packages? 
> Basically by making a separate package for each firmware file (or 
> driver). This works because there are not too many of them, but having a 
> huge number of tiny packages is a nightmare by itself.
> 
> But anyway, the dep-pkg target will have to be made smarter than it is now 
> if it's to deal with this [1]. And at least currently it is broken.
> 
> If I were able to compile firmware into the modules, the problem would be 
> solved in one go.
> 
> I don't know how the Debian kernel team plans to deal with this for distro 
> kernel packages. They probably _do_ want to keep them separate [2]. Maybe 
> by grouping firmware for really common drivers into 
> firmware-basic-drivers or something along those lines.
> 
> Cheers,
> FJP
> 
> [1] Only quick solution I see is to have it install the firmware in a 
> versioned directory and have the postinst copy things from there to
> /lib/firmware.

using /lib/firmware/`uname -r`/ is actually not a bad idea. You only
have to fix udev to actually include this in the list of directories to
look for firmware files. Also Ubuntu is already doing this.

Regards

Marcel


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