On Fri, May 26 2006, Jeff Garzik wrote:
> Jens Axboe wrote:
> >On Fri, May 26 2006, zhao, forrest wrote:
> >>For ata_piix resume operation, it first waits for BUSY bit clear,
> >>then calls ata_device_resume().
> >
> >This has the problem that it introduces scsi specific knowledge into
> >ata_piix, something that is both a violation and a problem because we
> >are moving libata away from scsi. I think the best way to currently do
> >this is to introduce a ata_port_ops hook (pre_resume()?) that waits for
> >busy clear and gets called in ata_device_resume is probably the way to
> >go.
>
> ata_device_resume() is fine as-is. Modifying it to resurrect the bus is
> a gross layering violation. Resume must be done in this order:
>
> controller -> bus -> device
>
> Thus, the bus must be resurrected and brought to a known HSM state (bus
> idle), and then ata_device_resume() will work just fine.
>
> The proper solution is to modify the pci_driver::resume code path, to
> resurrect not only the HBA but also the ATA bus. Currently we have
> ata_pci_device_{suspend,resume}, whose contents is wholly generic to any
> random PCI device.
>
> I would suggest creating pata_pci_device_resume(), which calls
> ata_pci_device_resume(), and then waits for BSY to clear.
I thought about that, and I don't agree. Waiting for the BSY to clear is
not a pci property, at best I'd consider that even worse than defining a
scsi resume function in ata_piix.
--
Jens Axboe
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