Message-ID: <4462B737.80108@gmx.net>
Date: Thu, 11 May 2006 06:01:59 +0200
From: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
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To: Dave Jones <davej@redhat.com>
CC: Greg KH <gregkh@suse.de>, Pavel Machek <pavel@suse.cz>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, trenn@suse.de,
       thoenig@suse.de
Subject: Re: [RFC] [PATCH] Execute PCI quirks on resume from suspend-to-RAM
References: <446139FF.205@gmx.net> <20060510093942.GA12259@elf.ucw.cz> <4461C0CA.8080803@gmx.net> <20060510205600.GB23446@suse.de> <44625CE9.2060204@gmx.net> <20060511023109.GB11693@redhat.com>
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Dave Jones wrote:
> On Wed, May 10, 2006 at 11:36:41PM +0200, Carl-Daniel Hailfinger wrote:
>  > Greg KH wrote:
>  > > On Wed, May 10, 2006 at 12:30:34PM +0200, Carl-Daniel Hailfinger wrote:
>  > >> Thinking about it again, if we restored the full pci config space
>  > >> on resume, this quirk handling would be completely unnecessary.
>  > >> Any reasons why we don't do that?
>  > > 
>  > > We do do that.  Look at pci_restore_state().
>  > > 
>  > > Actually, look at it in the latest -mm tree, that version works better
>  > > than mainline does right now :)
>  > 
>  > Sorry. Even the version in -mm does not restore all 256 bytes, so it
>  > will not change anything.
> 
> You can't generically look at a PCI device past the first 32 bytes.
> *anything* could be there, including registers which cause the machine
> to lock up when they get read.
> 
> This is exactly the reason that lspci by default only shows 32 bytes,
> and you need to be root to see past that limit.

You mean 64 bytes?

>  > So either we really restore the full config space (probably a good idea
>  > by itself)
> 
> No, *really* *really* bad idea :)

I had hoped the warnings in the lspci man page would be obsolete now.
Wishful thinking, it appears. Thanks for the hint.


Unfortunately, that means we either have to introduce a new PCI_FIXUP_
type or we execute PCI_FIXUP_HEADER also on resume. Which is better?


Regards,
Carl-Daniel
-- 
http://www.hailfinger.org/
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