FreeBSD 11 not sending repeated TURs until good status returned?

[Alan Somers]

On Tue, Dec 19, 2017 at 12:30 PM, Rebecca Cran <rebecca at bluestop.org> wrote:

> I've been asked about a bug report at $work for a SAS drive, which is
> failing to be detected when hot-plugged under FreeBSD 11 since I used to be
> a FreeBSD developer. Not being being familiar with the *scsi* code however,
> I thought people on this mailing list might have a better idea!
>
> From the report:
>
> "[the affected drive] is more closely conforming to the T10 spec as a Mode
> Sense command does not require media access."
>
> "The proper thing for the system to do is send repeated TURs to the drive
> until good status is returned. After that moment, the drive can properly do
> I/O."
>
>
>
> The log file contains:
>
>   READ(10). CDB: 28 00 2e 93 90 af 00 00 01 00
>
>   CAM status: SCSI Status Error
>
>   SCSI status: Check Condition
>
>   SCSI sense: NOT READY asc:4,1 (Logical unit is in process of becoming
> ready)
>
>   Progress: 0% (2/65536) complete
>
>   Polling device for readiness
>
>   mpssas_prepare_remove: Sending reset for target ID 123
>
> da12 at mps0 bus 0 scbus0 target 123 lun 0
>
> ...
>
>
> Does this sound like a valid bug?
>

What's the problem exactly?  Does FreeBSD poll the device or not?   Does
FreeBSD give up too soon, or poll with the wrong command, or what?  And if
you don't mind me asking, what sort of drive is this that takes so long to
come ready?

-Alan