Re: [BUGFIX 1/4] PCI/PM: enable D3/D3cold by default for most devices

[Rafael J. Wysocki]

On Friday, August 03, 2012, Huang Ying wrote:
> This patch fixes the following bug:
> 
> http://marc.info/?l=linux-usb&m=134318961120825&w=2
> 
> Originally, device lower power states include D1, D2, D3.  After that,
> D3 is further divided into D3hot and D3cold.  To support both scenario
> safely, original D3 is mapped to D3cold.
> 
> When adding D3cold support, because worry about some device may have
> broken D3cold support, D3cold is disabled by default.  This disable D3
> on original platform too.  But some original platform may only have
> working D3, but no working D1, D2.  The root cause of the above bug is
> it too.
> 
> To deal with this, this patch enables D3/D3cold by default for most
> devices.  This restores the original behavior.  For some devices that
> suspected to have broken D3cold support, such as PCIe port, D3cold is
> disabled by default.
> 
> Reported-by: Bjorn Mork <bjorn@xxxxxxx>
> Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx>

Reviewed-by: Rafael J. Wysocki <rjw@xxxxxxx>

> ---
>  drivers/pci/pci.c              |    1 +
>  drivers/pci/pcie/portdrv_pci.c |    5 +++++
>  2 files changed, 6 insertions(+)
> 
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1941,6 +1941,7 @@ void pci_pm_init(struct pci_dev *dev)
>  	dev->pm_cap = pm;
>  	dev->d3_delay = PCI_PM_D3_WAIT;
>  	dev->d3cold_delay = PCI_PM_D3COLD_WAIT;
> +	dev->d3cold_allowed = true;
>  
>  	dev->d1_support = false;
>  	dev->d2_support = false;
> --- a/drivers/pci/pcie/portdrv_pci.c
> +++ b/drivers/pci/pcie/portdrv_pci.c
> @@ -200,6 +200,11 @@ static int __devinit pcie_portdrv_probe(
>  		return status;
>  
>  	pci_save_state(dev);
> +	/*
> +	 * D3cold may not work properly on some PCIe port, so disable
> +	 * it by default.
> +	 */
> +	dev->d3cold_allowed = false;
>  	if (!pci_match_id(port_runtime_pm_black_list, dev))
>  		pm_runtime_put_noidle(&dev->dev);
>  
> 
> 

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