Re: [PATCH] PCI / PM: Use per-device D3 delays

From: Andreas Mohr
Date: Fri Jan 01 2010 - 15:12:55 EST


Hi,

On Fri, Jan 01, 2010 at 07:55:27PM +0100, Rafael J. Wysocki wrote:
> On Friday 01 January 2010, Andreas Mohr wrote:
> > Hi,
> >
> > While the bug report mentions "So it's just quirky hardware.",
> > the implementation of your patch makes it seem like this delay attribute is
> > totally "norm"al behaviour - I'm missing some more aggressive wording.
>
> That's because it works both ways (please look at the changelog).

Ah, ok.

> I know of a few devices that don't need the PCI-prescribed 10 ms wait when
> going from D3 to D0 and their drivers may use the d3_delay field to actually
> set a _shorter_ delay.

Then why is the value lower-bounded by pci_pm_d3_delay
(which, puzzlingly, was initialized to PCI_PM_D3_WAIT and thus 10
before, which the patch now removes!), in pci_dev_d3_sleep()?
(and pci_pm_d3_delay is being quirked in drivers/pci/quirks.c only,
to 120)

Confused,

Andreas Mohr
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