Re: [RFC] firmware leaves device in D3hot at boot

Greg KH
2005-06-30T19:29:43Z

On Thu, Jun 23, 2005 at 10:28:07PM -0400, John W. Linville wrote:
> On Thu, Jun 23, 2005 at 03:14:52PM -0400, John W. Linville wrote:
>
> > This issue regarding D3hot->D0 state transitions seems like a piece
> > of minutiae that we should not force individual drivers to address.
>
> After some thought, I'm inclined to think that the patch below is
> the right one. It unconditionally saves and restores the PCI config
> registers when pci_enable_device is called. Although this is often
> (usually?) unnecessary, it seems like a safe thing to do and it should
> not be a performance-sensitive path. The code to check for whether
> or not this is necessary would be a little harder to read IMHO,
> so I think this is warranted.

But how does this solve your problem with the state change?

> The comment block at the head of pci_enable_device says "Initialize
> device before it's used by a driver" which implies that saving and
> restoring the PCI config should be safe if the function is used
> as intended.

All pci drivers must call pci_enable_device() before they start to use
it.

thanks,

greg k-h