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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Gerd Knorr <kraxel@bytesex.org>
Cc: Dave Jones <davej@redhat.com>, Andrew Morton <akpm@osdl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: MTRR vesafb and wrong X performance
Date: Mon, 29 Nov 2004 17:22:24 +0000	[thread overview]
Message-ID: <1101748942.21239.8.camel@localhost.localdomain> (raw)
In-Reply-To: <20041129173419.GC26190@bytesex>

On Llu, 2004-11-29 at 17:34, Gerd Knorr wrote:
> Thats kida silly, but as I've found some simliar construct in the old
> code I left it in to avoid breaking stuff.  Guess there is a reason that
> this was there.  I'll take that as proof that broken BIOSes exist which
> don't fill screen_info.lfb_size correctly ;)

Indeed. Also some report less than the full amount because they only
support VGA modes in the lower bits of memory and others like Intel
ICH/GCH based systems report 1Mb because in essence the question has no
right answer.

> Maybe it works better to walk the PCI device list, find the correct
> gfx card using the framebuffer start address, then double-check the
> size by looking at the PCI ressources?

Very very few cards have a PCI resource map that gives useful size
information because they have apertures and are sometimes also windowed
or not all CPU accessible.


  reply	other threads:[~2004-11-29 18:26 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-11-24 23:15 Pawel Fengler
2004-11-25  1:18 ` Andrew Morton
2004-11-25 21:56   ` Pawel Fengler
2004-11-29 11:12     ` Gerd Knorr
2004-11-29 15:40       ` Dave Jones
2004-11-29 16:22         ` Gerd Knorr
2004-11-29 16:57           ` Dave Jones
2004-11-29 17:34             ` Gerd Knorr
2004-11-29 17:22               ` Alan Cox [this message]
2004-11-29 18:17               ` Dave Jones
2004-11-29 17:23                 ` Alan Cox
2004-11-29 16:24         ` Alan Cox
2004-11-25  8:49 ` Gerd Knorr
2004-11-26 16:48 Pawel Fengler

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