linux-kernel - Re: platform/x86: p2sb: Allow p2sb_bar() calls during PCI device probe

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Message-ID: <ZzdhTsuRNk1YWg8p@goliath>
Date: Fri, 15 Nov 2024 14:57:19 +0000
From: "Daniel Walker (danielwa)" <danielwa@...co.com>
To: Shinichiro Kawasaki <shinichiro.kawasaki@....com>
CC: Hans de Goede <hdegoede@...hat.com>, Andy Shevchenko
	<andriy.shevchenko@...ux.intel.com>, Ilpo J�rvinen
	<ilpo.jarvinen@...ux.intel.com>, Klara Modin <klarasmodin@...il.com>, Greg
 Kroah-Hartman <gregkh@...uxfoundation.org>, Danil Rybakov
	<danilrybakov249@...il.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "xe-linux-external(mailer list)"
	<xe-linux-external@...co.com>
Subject: Re: platform/x86: p2sb: Allow p2sb_bar() calls during PCI device
 probe

On Fri, Nov 15, 2024 at 11:35:46AM +0000, Shinichiro Kawasaki wrote:
> On Nov 13, 2024 / 19:34, Hans de Goede wrote:
> > Hi,
> > 
> > On 13-Nov-24 6:41 PM, Daniel Walker (danielwa) wrote:
> > > On Wed, Nov 13, 2024 at 06:04:44PM +0100, Hans de Goede wrote:
> > >> Hi,
> > >>
> > >> On 13-Nov-24 5:33 PM, Hans de Goede wrote:
> > >>> Hi,
> > >>>
> > >>> On 13-Nov-24 5:24 PM, Hans de Goede wrote:
> [...]
> > >>> It probably has something to do with these 2 messages:
> > >>>
> > >>> pci 0000:00:1f.1: BAR 0 [mem 0xfd000000-0xfdffffff 64bit]: can't claim; no compatible bridge window
> > >>> pci 0000:00:1f.1: BAR 0 [mem 0x280000000-0x280ffffff 64bit]: assigned
> > >>>
> > >>> I'm guessing that this re-assignment is messing up
> > >>> the p2sb BAR caching, after which things go wrong.
> > >>
> > >> Hmm, but that should be fixed by 2c6370e66076 ("platform/x86: p2sb: Don't init until unassigned resources have been assigned")
> > >>
> > >> and you are seeing this with 6.12, which has that.
> > >>
> > >> Can you try adding a pr_info() to the top of p2sb_cache_resources()
> > >> with 6.12 and then collec a new dmesg ?
> > >>
> > >> If that pr_info() is done after the:
> > >>
> > >> pci 0000:00:1f.1: BAR 0 [mem 0x280000000-0x280ffffff 64bit]: assigned
> > >>
> > >> message then that does not explain things.
> > >>
> > > 
> > > I haven't testing adding a pr_info() but the messages seem to happen in the same
> > > order in both working and non-working cases.
> > > 
> > > Does that matter?
> > 
> > The working case does not do the bar caching, we want to know if the
> > bar caching in the non working case happens before or after the assignment:
> > 
> > pci 0000:00:1f.1: BAR 0 [mem 0x280000000-0x280ffffff 64bit]: assigned
> > 
> > It should happen after the assignment.
> 
> Hello Daniel,
> 
> It's my sorrow that the change cause this trouble. I have created a debug patch
> for the kernel and attached to this e-mail. It adds some pr_info() to answer
> the question from Hans. It will also show us a bit more things. Could you try it
> on your system? It should apply to v6.12-rcX kernels without conflicts.
> 

Ok.. The dmesg with the patch applied is attached.

Daniel



Download attachment "dmesg-debug.txt.gz" of type "application/gzip" (9079 bytes)