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

[Nathan Bryant <nbryant@optonline.net>]

Benjamin Herrenschmidt wrote:

> Note regarding aix7xxx, we also need proper hooks in the SCSI stack to
> block the queue correctly etc... in the same way we do on IDE. I didn't
> have time to look into this yet.

Here's what we currently do, aic7xxx_core.c - looks like it attempts to 
quiesce, and then refuse to suspend if we happen to be busy. This is a 
little messy because it's done in the suspend call rather than the 
save_state call, therefore resume will still be called if this routine 
returns an error code, which will reinitialize the device when we didn't 
really need to.

int
ahc_suspend(struct ahc_softc *ahc)
{

         ahc_pause_and_flushwork(ahc);

         if (LIST_FIRST(&ahc->pending_scbs) != NULL) {
                 ahc_unpause(ahc);
                 return (EBUSY);
         }

#ifdef AHC_TARGET_MODE
         /*
          * XXX What about ATIOs that have not yet been serviced?
          * Perhaps we should just refuse to be suspended if we
          * are acting in a target role.
          */
         if (ahc->pending_device != NULL) {
                 ahc_unpause(ahc);
                 return (EBUSY);
         }
#endif
         ahc_shutdown(ahc);
         return (0);
}