linux-kernel - Re: 2.6.29-rc3: tg3 dead after resume

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Message-ID: <20090129021944.GA12879@xw6200.broadcom.net>
Date:	Wed, 28 Jan 2009 18:19:44 -0800
From:	"Matt Carlson" <mcarlson@...adcom.com>
To:	"Linus Torvalds" <torvalds@...ux-foundation.org>
cc:	"Parag Warudkar" <parag.lkml@...il.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
	"David S. Miller" <davem@...emloft.net>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"Matthew Carlson" <mcarlson@...adcom.com>
Subject: Re: 2.6.29-rc3: tg3 dead after resume

On Wed, Jan 28, 2009 at 06:10:37PM -0800, Linus Torvalds wrote:
> 
> 
> On Wed, 28 Jan 2009, Parag Warudkar wrote:
> > 
> > Sure, diff -u below. There are differences but not sure if they are 
> > abnormal or expected.
> 
> Well, they're all in the "extended set", ie not the basic registers that 
> the PCI layer saves. The PCI layer normally just saves the low 16 dwords, 
> along with the PCI[EX] capability thing.
> 
> None of the PCI save/restore routines have ever saved the extended state 
> (well, "ever" is a strong word - I think we long ago used to pass in how 
> many bytes we wanted saved, but got rid of it), and it certainly didn't 
> change with the recent PCI suspend/resume changes.
> 
> I get the feeling that it's some odd tg3 issue. That tg3 driver does have 
> that special
> 
>         /* Make sure register accesses (indirect or otherwise)
>          * will function correctly.
>          */
>         pci_write_config_dword(tp->pdev,
>                                TG3PCI_MISC_HOST_CTRL,
>                                tp->misc_host_ctrl);
> 
> in its own version of setting the power state, and maybe that really 
> _must_ happen before we actually set the state back to PCI_D0. That sounds 
> very odd, but hey..
> 
> I added Matt Carlson to the cc, since he seems to be the main tg3 
> authority here.
> 
> Matt: the whole discussion is on netdev and the kernel mailing list, but 
> the short version is that -rc3 suspends and resumes for Parag again 
> (unlike -rc2), but tg3 doesn't appear to resume properly. The generic PCI 
> layer now does more at resume time (very early, when interrupts are still 
> off), see
> 
>  - pci_pm_resume_noirq ->
>      pci_pm_default_resume_noirq() ->
>        pci_restore_standard_config()
> 
> for more of the details (basically it always does that 
> "pci_restore_state()" and tries to bring the device back to PCI_D0).

Thanks Linus.  I'm looking over the diffs Parag sent and I already see
some suspicious register settings.  Let me think about this some more
and then I'll jump into the discussion.

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