CAM suspend

Jia-Shiun Li jsli at
Thu Oct 2 11:21:59 PDT 2003

Since the memory content will be kept across suspension,
I guess there is no need for da to take special care.
Just like what ad does.
The actual suspend/resume method is for ata-pci.

For hardware devices to come back to previous state,
the correct place may be in SCSI HBA driver like ahc, sym, etc.?


Walter C. Pelissero wrote:
> Having noticed that there is not a big interest in it, among the
> fellow FreeBSDers, I was about to set off and hack up the scsi
> subsystem to implement spindown on suspend and spinup on resume of the
> da devices, when I realized that there seems to be no hook in the SCSI
> code for this events.
> I'm not a device driver expert, so I'm looking for clues.
> What I mean is that the ata-pci driver, for instance, specifies hooks
> via the device_method_t structure which is not available in the
> scsi_all or scsi_da modules.  I understand that they are simply
> different kind of beasts (sitting on different layers of the kernel
> code), but I was wondering if there might be a similar mechanism to do
> what I want.
> So, what is the recommended way (if there is one), to hook a function
> of the SCSI subsystem to an event like suspend/resume?
> I would most appreciate if anyone could point me to a suitable
> document or even anything related to FreeBSD kernel hacking.
> Cheers,

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