linux-kernel - Re: [RFC/PATCH 0/4] request_firmware() on memory constrained devices

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Date:	Tue, 08 Mar 2016 17:07:38 +0700
From:	Stephen Boyd <stephen.boyd@...aro.org>
To:	Alexander Stein <alexander.stein@...tec-electronic.com>,
	linux-kernel@...r.kernel.org
Cc:	linux-arm@...ts.infradead.org,
	"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
	"Robin Murphy" <robin.murphy@....com>,
	"Laura Abbott" <labbott@...hat.com>,
	"Arnd Bergmann" <arnd@...db.de>,
	"Marek Szyprowski" <m.szyprowski@...sung.com>,
	"Mimi Zohar" <zohar@...ux.vnet.ibm.com>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Mark Brown" <broonie@...nel.org>,
	"Catalin Marinas" <catalin.marinas@....com>,
	"Will Deacon" <will.deacon@....com>
Subject: Re: [RFC/PATCH 0/4] request_firmware() on memory constrained devices

Quoting Alexander Stein (2016-03-08 16:32:21)
> On Tuesday 08 March 2016 16:22:15, Stephen Boyd wrote:
> > Some systems are memory constrained but they need to load very
> > large firmwares. 
> 
> Out of curiousity, about which sizes of memory and firmware are you talking about?
> 

Hm.. I've seen an extreme case where there's around 100MB of a 128MB DDR
part dedicated to non-Linux firmware. So attempting to load that
firmware into DDR just doesn't work at all unless you have this patch
series. This is the most extreme case I've seen though.

Please also note that this is also about skipping the memcpy() step,
which I should probably quantify how much that actually matters if at
all. I'll make sure to do some loading time measurements in the next
round.