Re: Shutting down PCI devices on suspend

[Matthew Garrett <mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org>]

On Sat, 2004-12-11 at 11:50 -0800, Nate Lawson wrote:
> In FreeBSD, we do this at the bus layer.  So the ACPI and PCI bus code 
> is responsible for powering down/up children.  We currently do it:
> 
> 1. When no driver is attached and on reprobe
> 2. When suspending/resuming, based on evaluating _SxD
> 
> See this commit for details:
> http://docs.freebsd.org/cgi/getmsg.cgi?fetch=1604853+0+archive/2004/cvs-all/20041205.cvs-all

Does _SxD represent the "desired" mode for the hardware, or merely the
highest state it can be left in? A mail from Len earlier this year
suggested that if S3D returned 0x2, that meant that either D3 or D2 were
acceptable.

Is there any reason why adding something like

if (state==3) {
	pci_set_power_state(dev,ACPI_STATE_D3COLD)
}

to pci_device_suspend in the non-driver path and reenabling it in
pci_default_resume would result in things breaking?

(Possibly with sanity checks as to whether it's a bridge or not)

-- 
Matthew Garrett | mjg59-1xO5oi07KQx4cg9Nei1l7Q@public.gmane.org



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