linux-kernel - Re: [PATCH] pci: Don't enable aspm before drivers have had a chance to veto it

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Message-ID: <20100618091255.2db036ea@virtuousgeek.org>
Date:	Fri, 18 Jun 2010 09:12:55 -0700
From:	Jesse Barnes <jbarnes@...tuousgeek.org>
To:	Maxim Levitsky <maximlevitsky@...il.com>
Cc:	Matthew Garrett <mjg@...hat.com>,
	Jussi Kivilinna <jussi.kivilinna@...et.fi>,
	"Luis R. Rodriguez" <mcgrof@...badil.infradead.org>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] pci: Don't enable aspm before drivers have had a chance
 to veto it

On Fri, 18 Jun 2010 15:06:51 +0300
Maxim Levitsky <maximlevitsky@...il.com> wrote:

> On Wed, 2010-06-09 at 16:05 -0400, Matthew Garrett wrote: 
> > The aspm code will currently set the configured aspm policy before drivers
> > have had an opportunity to indicate that their hardware doesn't support it.
> > Unfortunately, putting some hardware in L0 or L1 can result in the hardware
> > no longer responding to any requests, even after aspm is disabled. It makes
> > more sense to leave aspm policy at the BIOS defaults at initial setup time,
> > reconfiguring it after pci_enable_device() is called. This allows the
> > driver to blacklist individual devices beforehand.
> > 
> > Signed-off-by: Matthew Garrett <mjg@...hat.com>
> > ---
> 
> Hi,
> 
> I recently discovered that my aspire one wireless troubles (card just
> dies after a while) are caused by ASPM L0S state.
> The device (AR5001) seems to have a hardware bug, and it also disables
> L0S in windows driver.
> 
> Unfortenuly BIOS (news at 11) enables L0S.
> 
> Its easy to disable ASPM from driver. It just a matter of calling
> pci_disable_link_state.
> 
> However, that depends on CONFIG_PCIEASPM.
> 
> How about making pci_disable_link_state always available or even better,
> just make CONFIG_PCIEASPM unconditional?

The former is ok with me.  Care to post a patch?

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center
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