Re: [PATCH] scsi: core: Add BLIST_NO_ASK_VPD_SIZE for some VDASD

From: Martin K. Petersen
Date: Mon Nov 07 2022 - 21:50:53 EST



Hannes,

I have been contemplating this for a bit.

>> Has it been considered instead of introducing a blacklist flag to not
>> use the reported VPD page size if the device reports that the VPD
>> page size is zero? I am not aware of any VPD pages for which zero is
>> a valid size.

That would also be my preferred approach, I think. I haven't received
any bug reports about devices returning short VPD pages since this
change was introduced. So I think I'd prefer falling back to a
(hopefully small) default if a device returns a 0 page length.

Now, my question is which VPD pages are actually supported by this
device and how large are they?

> But pre-SPC drives will ignore the VPD bit in the inquiry size. And
> these devices do not set an additional length in the inquiry data

Can you elaborate a bit on your experience with older devices? I checked
SCSI-2 (1991) and don't see any indication this would be valid behavior
even back then.

--
Martin K. Petersen Oracle Linux Engineering