From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir@xensource.com>
Subject: Re: early_cpu_init() and identify_cpu()
Date: Tue, 17 Jul 2007 08:55:08 +0100
Message-ID: <C2C2346C.128BF%keir@xensource.com>
References: <20070716102329.62b8bf17@the-village.bc.nu>
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To: Alan Cox <alan@lxorguk.ukuu.org.uk>, Jan Beulich <jbeulich@novell.com>
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On 16/7/07 10:23, "Alan Cox" <alan@lxorguk.ukuu.org.uk> wrote:

>> significant (though I assume WC would at best help a little, I'm considering
>> other approaches, too): Scrolling a 1280x1024x16 screen takes, on the test
>> system I'm primarily trying this out on, on the order of a second. This is
> 
> A lot of work on this has been done in X by the X and Gnome developers
> including producing some routines which use the largest possible aligned
> loads to reduce the big cost (which is PCI reads). Having a write
> combining video memory can help (but some cards also put stuff like
> command queues there which X cannot WC).

Does this mean that defaulting to setting up WC on a power-of-two-sized
region starting at the framebuffer address is not really safe on a fair
number of systems?

 -- Keir