Re: [PATCH] PCI / PM: Use per-device D3 delays
From: Jesse Barnes
Date: Mon Jan 04 2010 - 18:48:17 EST
On Thu, 31 Dec 2009 12:15:54 +0100
"Rafael J. Wysocki" <rjw@xxxxxxx> wrote:
> From: Rafael J. Wysocki <rjw@xxxxxxx>
>
> It turns out that some PCI devices require extra delays when changing
> power state from D3 to D0 (and the other way around). Although this
> is against the PCI specification, we can handle it quite easily by
> allowing drivers to define arbitrary D3 delays for devices known to
> require extra time for switching power states.
>
> Introduce additional field d3_delay in struct pci_dev and use it to
> store the value of the device's D0->D3 delay, in miliseconds. Make
> the PCI PM core code use the per-device d3_delay unless
> pci_pm_d3_delay is greater (in which case the latter is used).
> [This also allows the driver to specify d3_delay shorter than the
> 10 ms required by the PCI standard if the device is known to be able
> to handle that.]
>
> Make the sky2 driver set d3_delay to 150 for devices handled by it.
>
> Fixes http://bugzilla.kernel.org/show_bug.cgi?id=14730 which is a
> listed regression from 2.6.30.
>
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Applied to my for-linus branch, thanks.
--
Jesse Barnes, Intel Open Source Technology Center
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