Re: /sys/module/pcie_aspm/parameters/policy not writable?

From: Pavel Machek <pavel@ucw.cz>
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: Greg KH <greg@kroah.com>,
	kernel list <linux-kernel@vger.kernel.org>,
	Joe Lawrence <joe.lawrence@stratus.com>,
	Myron Stowe <myron.stowe@redhat.com>,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Bruce Allan <bruce.w.allan@intel.com>,
	Carolyn Wyborny <carolyn.wyborny@intel.com>,
	Don Skidmore <donald.c.skidmore@intel.com>,
	Greg Rose <gregory.v.rose@intel.com>,
	Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>,
	Alex Duyck <alexander.h.duyck@intel.com>,
	John Ronciak <john.ronciak@intel.com>,
	Tushar Dave <tushar.n.dave@intel.com>,
	"e1000-devel@lists.sourceforge.net" 
	<e1000-devel@lists.sourceforge.net>
Subject: Re: /sys/module/pcie_aspm/parameters/policy not writable?
Date: Fri, 2 Aug 2013 03:02:59 +0200	[thread overview]
Message-ID: <20130802010259.GA4779@amd.pavel.ucw.cz> (raw)
In-Reply-To: <CAErSpo4Dw9Bg059scx-YzR=5rpkc65f0hjQnM7STtoprOLXJqw@mail.gmail.com>

Hi!

> >> > But since the problem also occurs with Windows, it's pretty likely
> >> > that there's a BIOS update to fix it.  I notice on the X60 support
> >> > page that there are several versions newer than what you're running.
> >>
> >> Do you have any interest in trying a newer BIOS to see if it's fixed
> >> there?  If not, I understand; BIOS updates are a hassle at best.
> >> You're running BIOS 2.14, and it looks like the current BIOS for an
> >> X60 1709 7HU is 2.19 (from http://support.lenovo.com).
> >
> > I'm lost at the lenovo pages :-(. And frankly I'd prefer not to touch
> > the BIOS.
> 
> I tried to provide a complete link, but the web site isn't amenable to
> that.  I found it by selecting the "Drivers & Software" section,
> entering "X60" as the machine type, selecting "ThinkPad X60 (1709)"
> and going to the "BIOS" section.  I was surprised how easy it was :)

Ok, got it, the web pages are horible.

> >> Carolyn's patch will likely work, at least most of the time, but I
> >> think there's a small possibility that it could cause a conflict
> >> between the BIOS and the OS over ASPM control, so I'm not 100% in
> >> support of that approach.  A conflict may not happen on your
> >> machine,
> >
> > Can we base it on DMI  whitelist?
> 
> I don't think we can know a priori whether a machine (even your
> machine) is susceptible to a conflict.  But if Carolyn forcibly
> disables it in the driver, she can structure that with a whitelist or
> whatever she thinks is best.

Well, there's only one way to find out: try it. I was running with the
"enable ASPM so we can disable it" one-liner for a while, and seen no
ill effects.

Anyway, if you don't hear from me again, it means that I have a brick
(and not a notebook) and am desperately trying to get replacement
X60. Will try to flash it in few minutes.
     	   	     	    		       	      		       Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html