netdev - Re: is L1 really disabled in iwlwifi

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Date:	Fri, 17 May 2013 08:49:01 +0300
From:	Emmanuel Grumbach <egrumbach@...il.com>
To:	Bjorn Helgaas <bhelgaas@...gle.com>
Cc:	Matthew Garrett <matthew.garrett@...ula.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Stanislaw Gruszka <sgruszka@...hat.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	linux-wireless <linux-wireless@...r.kernel.org>,
	John Linville <linville@...driver.com>,
	Roman Yepishev <roman.yepishev@...il.com>,
	"Guy, Wey-Yi" <wey-yi.w.guy@...el.com>,
	Mike Miller <mike.miller@...com>,
	"iss_storagedev@...com" <iss_storagedev@...com>,
	Guo-Fu Tseng <cooldavid@...ldavid.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Francois Romieu <romieu@...zoreil.com>,
	"nic_swsd@...ltek.com" <nic_swsd@...ltek.com>,
	"aacraid@...ptec.com" <aacraid@...ptec.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: is L1 really disabled in iwlwifi

>
> I couldn't imagine that silently ignoring the request to disable ASPM
> would be the right thing, but I spent a long time experimenting with
> Windows on qemu, and I think you're right.  Windows 7 also seems to
> ignore the "PciASPMOptOut" directive when we don't have permission
> to manage ASPM.  All the gory details are at
> https://bugzilla.kernel.org/show_bug.cgi?id=57331
>
> The current behavior is definitely confusing.  I hate to rename or change
> pci_disable_link_state() because it's exported and we'd have to maintain
> the old interface for a while anyway.  And I don't really want to return
> failure to drivers, because I think that would encourage people to fiddle
> with the Link Control register directly in the driver, which doesn't seem
> like a good idea.
>
> And you're also right that (as far as I know) there's not an actual
> problem with the current behavior other than the confusion it causes.
>
> So, how about something like the following patch, which just prints a
> warning when we can't do what the driver requested?  I suppose this may
> also be a nuisance, because users will be worried, but they can't actually
> *do* anything about it.  Maybe it should be dev_info() instead.
>

Good for me - now I would be notified that something wrong happened.
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