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List:       linux-kernel
Subject:    Re: [PATCH] yet another yenta resource allocation fix
From:       Martin Diehl <lists () mdiehl ! de>
Date:       2001-09-30 23:19:32
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On Mon, 1 Oct 2001, Alan Cox wrote:

> > I'm asking for application of a patch I'm using since 2.4.0. Issue was the
> > BIOS of my OB-800 mapped the memory regions of the cardbus bridges into
> > legacy 1M-area (0xe6000 e.g.). Despite being pretty bogus this used to
> > work after a reboot just until the first pm-suspend/resume, where the
> > hostbridge somehow looses access to this area.
> 
> At a guess your bios doesnt restore the shadow ram disables right.

In fact, there is a (IIRC single) byte changed in the hostbridge's config
space after resume. Blindly writing back the old value re-enables access
to the cardbus memory resource below 1M. But I agree solving the real
cause (i.e. bogus mapping to legacy area) is better then trying to cure
whatever triggers the problem with that.

> Would a generic
> 
> 	pci_fixup_device()
> 
> type function not be more appropriate

IIRC there was some discussion on l-k some time ago, whether such fixups
should stay close to were the issue appeared or better be placed at
generic pci quirk location. In this particular case I personally tend to
the latter one as well, particularly because there may be other BIOS'
doing similar things with non-cardbus memory bar's.
The patch however was simply what I'm using since 2.4.0 just in case the
cardbus-specific fixup would be the prefered way.

Martin

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