linux-kernel - Re: Help needed, Re: [Bug #14334] pcmcia suspend regression from 2.6.31.1 to 2.6.31.2

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Message-ID: <1256947041.6372.165.camel@pasglop>
Date:	Sat, 31 Oct 2009 10:57:21 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Kernel Testers List <kernel-testers@...r.kernel.org>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	Jose Marino <braket@...mail.com>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Linux PCI <linux-pci@...r.kernel.org>,
	Dominik Brodowski <linux@...inikbrodowski.net>
Subject: Re: Help needed, Re: [Bug #14334] pcmcia suspend regression from
 2.6.31.1 to 2.6.31.2 - Dell Inspiron 600m

On Fri, 2009-10-30 at 12:47 -0700, Linus Torvalds wrote:
> 
> On Fri, 30 Oct 2009, Rafael J. Wysocki wrote:
> > 
> >
> > 1) Resume works if pcmcia_socket_dev_resume(dev) is moved to the "regular"
> >    resume phase, after resume_device_irqs().
> 
> Hmm. We really probably shouldn't call pcmcia_socket_dev_resume() in 
> early_resume. It takes mutexes etc, and it calls "socket_resume()", which 
> sleeps etc. That per se should be ok these days (since we don't actualyl 
> disable CPU irq's, just device irqs), but it also does that whole card 
> insertion events etc. And _that_ code I wouldn't trust at all.
> 
> The PCMCIA code is better than it used to be a long time ago, but some of 
> it is still pretty crazy. 
> 
> I get the feeling that we should just revert that commit 0c570cdeb, and 
> instead always do PCMCIA suspend as a "eject" event. That way we have no 
> driver behind it to resume at resume time - and we'll see any plugged-in 
> device as just a new insertion. 

To me the proper approach would be to split it so that

 - early_resume() restores power & config space etc... so that existing
devices can move on (might check for removal). There's no other hotplug
activity

 - normal resume() restarts handling of events such as insertions

Now, while I do have some cardbus & pcmcia stuff somewhere, I also don't
have much time to hack on this right now...

Cheers,
Ben.

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