Re: device_suspend() levels [was Re: [patch] ACPI work on aic7xxx]

Nathan Bryant
2004-07-26T14:01:41Z

Benjamin Herrenschmidt wrote:
> On Sat, 2004-07-24 at 20:19, Nathan Bryant wrote:
>
>>Benjamin Herrenschmidt wrote:
>>
>>
>>>That's different, because the disks are actually registered as
>>>"struct device" childs of the bus, and thus get proper suspend/resume
>>>callbacks.
>>
>>Ok, Seems like we rely on the BIOS a lot, here.
>
>
> How so ? not at all !

For suspend/resume and also initialization on bootup. We're not saving
the chip state for PIIX so I assume we're hoping that ACPI does it for us

> We need to issue the stuff from the low level driver (like aix7xxx) or
> the disk, that is sd, but we should make sure sg etc... also properly
> call the stuff, actually, look at IDE, I defined the special power
> request to act as a state machine once down the queue so the ide layer
> acts differently for disks, cdroms, etc... by sending appropriate
> commands like standby for disks.

There's another one - synchronize cache or disable write back cache on
the drive....