On Wednesday 04 February 2009, Linus Torvalds wrote:
>
> On Wed, 4 Feb 2009, Rafael J. Wysocki wrote:
> >
> > Suspend to RAM is reported to break on some machines as a result of
> > attempting to put one of driverless PCI devices into a low power
> > state. Avoid that by not attepmting to power manage driverless
> > devices during suspend.
> >
> > Fix up pci_pm_poweroff() after a previous incomplete fix for the same
> > thing during hibernation.
>
> Ok, I really don't like this patch, because:
>
> > -static void pci_pm_default_suspend(struct pci_dev *pci_dev)
> > +static void pci_pm_default_suspend(struct pci_dev *pci_dev, bool prepare)
> > {
> > pci_pm_default_suspend_generic(pci_dev);
> >
> > - if (!pci_is_bridge(pci_dev))
> > + if (prepare && !pci_is_bridge(pci_dev))
> > pci_prepare_to_sleep(pci_dev);
> >
> > pci_fixup_device(pci_fixup_suspend, pci_dev);
>
> This "helper" function really isn't helping anything at all any more. It's
> really just confusing things.
>
> Now that was true even before this all; mostly because your naming in this
> area _really_ sucks. I mean, what the heck is the difference between
> "pci_pm_default_suspend_generic()" and "pci_pm_default_suspend()", and
> what do they do?
>
> But you just made it worse. This trivial function that doesn't do anything
> interesting, and isn't well-named enough to actually explain what it is
> doing now became EVEN WORSE. Now it's a trivial function that does two
> things, except it does one of those things only if the magic flag (that is
> also not helpfully named) is set.
>
> Argh.
>
> To make it worse, it's not at all obvious what the logic is:
>
> > + struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> > + pci_pm_default_suspend(pci_dev, !!pm);
>
> Whaa? This is basically totally obfuscated code both in the caller _and_
> in the callee.
>
> Now, it looks like this all then goes away in PATCH 7/7, so I guess I
> shouldn't complain too much, but I just don't see much point in carrying
> this broken patch around in the series, since it's then going away and
> rewritten almost immediately again.
This is what has been tested by the bug reporter.
OK, I should have created a more sophisticated version, but that would go
away with patch 7/7 too, so ...
> Apart from that complaints, Acked-by: for the series.
Thanks!
Rafael
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