Re: [PATCH v5 2/2] PCI/PM: Fix pci_pm_suspend_noirq() to disable PTM

[Bjorn Helgaas]

On Thu, May 12, 2022 at 07:52:36PM +0200, Rafael J. Wysocki wrote:
> On Thu, May 12, 2022 at 7:42 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote:
> > On Thu, May 12, 2022 at 03:49:18PM +0200, Rafael J. Wysocki wrote:

> > > Something like this should suffice IMV:
> > >
> > > if (!dev_state_saved || pci_dev->current_state != PCI_D3cold)
> > >
> > >         pci_disable_ptm(pci_dev);
> >
> > It makes sense to me that we needn't disable PTM if the device is in
> > D3cold.  But the "!dev_state_saved" condition depends on what the
> > driver did.  Why is that important?  Why should we not do the
> > following?
> >
> >   if (pci_dev->current_state != PCI_D3cold)
> >     pci_disable_ptm(pci_dev);
> 
> We can do this too.  I thought we could skip the power state check if
> dev_state_saved was unset, because then we would know that the power
> state was not D3cold.  It probably isn't worth the hassle though.

Ah, thanks.  IMHO it's easier to analyze for correctness if we only
check the power state.

Bjorn