2007/477: Drivers registering devids

[Charles DeBardeleben]

Two more questions, and a comment.

The Solaris Cluster did driver is both a consumer and calls 
ddi_devid_register.
The device id that we register is related to the device id we consume.

Question 1. Does this mean that we need the new property? The intent is for
an instance of did to always have the same device id.

Question 2. If the disk under us moves, how do we discover this so that 
we can fix up our
layer open to get the correct disk under us.

Comment on virtual disk driver. Solaris cluster requires that anything 
that looks
like a disk or tape driver to have a device id. We require that vdc 
provide a device id.
Another thing, we require that the device id not change if the disk or 
virtual disk is still
the same. So if the device id presented is a fabricated device id, then 
it should be
stored persistently so that it is the same after reboot.

-Charles

Jerry Gilliam wrote:
>   
>>>    Immediate consumers (sd, ssd, cmdk, and dad target drivers) are all
>>>    in ON.  There are no contracts needed at this time. I am seeking
>>>    patch binding.
>>>       
>> There are two other drivers that use ddi_devid_register:
>> sata and vdc (ldom's virtual disk client) - should they be listed here ?
>>
>>     
>
> It wasn't apparent to me that vdc needs to provide this property
> for its encapsulated devid.  This is either an existing bug or
> there is no requirement.  I'll follow up on this.
>
> And with Prasad's work put back now, yes sata is now a devid
> registrant.
>
>
>   
>> What happens if a driver uses ddi_devid_register but the corresponding
>> driver.conf is not updated to have this flag ?
>>
>>     
>
> If the cache were to become damaged or the disk moved, the cache
> auto-rebuild mechanism would not include trying to configure that
> driver to re-discover the disk.
>
>
> -jg
>
>