On 09/07/2013 06:25 AM, David Herrmann wrote:
> On Sat, Sep 7, 2013 at 1:47 PM, Tom Gundersen <teg@xxxxxxx> wrote:
...
>> A related question: is it expected that simplefb should be
>> significantly slower than efifb, or is that something worth looking
>> into? My boot with simplefb is roughly five seconds slower than with
>> efifb. Coincidentally, I notice the same (or similar slowdown) with
>> inteldrmfb when I see the oops (but not otherwise).
>
> That is probably related to the missing write-combine tag in ioremap.
> Stephen, any objections to this attached patch?
> Tom, if this solves the speed-issues, I will send it out once I get home.
>
> Thanks
> David
>
> (Patch also attached in case of new-lines issues)
>
> From dbfb8e12166d494cd60823cbe84134d5d1a73ec8 Mon Sep 17 00:00:00 2001
> From: David Herrmann <dh.herrmann@xxxxxxxxx>
> Date: Sat, 7 Sep 2013 14:22:01 +0200
> Subject: [PATCH] devm/simplefb: introduce and use devm_ioremap_wc()
>
> We want to use devm_ioremap_nocache() or even devm_ioremap_wc() to speed
> up fbdev writes _a lot_. As devm_ioremap_wc() doesn't exist, yet,
> introduce it along the way. Note that ioremap_wc() is aliases to
> ioremap_nocache() in asm-generic/{io,iomem}.h so we can safely expect all
> architectures to either provide it or use the same alias.
OK, that works fine on the Raspberry Pi too, so,
Tested-by: Stephen Warren <swarren@xxxxxxxxxxxxx>
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