Pavel Roskin wrote:
>
> Hi, Jeff!
>
> Thanks for your very (!!!) fast response :-)
>
> > > http://www.red-bean.com/~proski/linux/ymfpci_pm.diff
> >
> > Why not use pci_driver::{suspend,resume} ?
>
> I'm just a bit conservative. There are several drivers that don't use this
> mechanism, notably trident and maestro. Do you think it's safe to switch
> all sound drivers to the mechanism you are proposing?
>
> I'm worried about a comment in maestro.c:
>
> /*
> * we'd also like to find out about
> * power level changes because some biosen
> * do mean things to the maestro when they
> * change their power state.
> */
>
> If we switch to pci_driver::{suspend,resume}, will it ever be possible to
> add support for any messages other than PM_SUSPEND and PM_RESUME? Probably
> yes, but only in the PCI driver dispatches them.
Basically the PCI core should implement what PM is necessary, because
eventually struct pci_driver will become a more generic struct driver.
When that happens, drivers using pci_driver::{suspend,resume} will
automagically work under the new system. To answer your question, the
PCI[/driver] core should support messages other than PM_{SUSPEND,RESUME}
if they need to be supported. Right now I mostly see suspend/resume
implemented and nothing else, so that is a very straightforward
conversion to the new PCI API.
Why does maestro.c not use my suggestion? Because it doesn't use struct
pci_driver.
Why does trident.c not use my suggestion? Only because noone has
written and tested the patch for it yet :) It uses struct pci_driver
and should be updated to use ::suspend/resume.
> > In ACPI land the kernel should save and restore the PCI device config
> > space and the PCI bus config space. It is probably that similar is
> > necessary under APM.
>
> I have never seen any sound driver doing that. I also know that PCI
> settings are saved by some BIOSes on some hardware.
That's because full PM support is still very much a work in progress :)
The linux-pm-devel sourceforge list has carried recent discussions, as
has linux-kernel. Patrick Mochel(sp?) @ Transmeta has posted a
hackers-only patch which incorporates my PCI PM work as well as his own
ACPI work to do suspend and resume.
--
Jeff Garzik | Game called on account of naked chick
Building 1024 |
MandrakeSoft |
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