[Smartmontools-database] USB external drive reports "Read Device Identity failed"

[Nathan Stratton Treadway]

On Fri, Dec 04, 2020 at 14:34:39 -0500, Robert Stocker wrote:
> That definitely looks like something I need to look at long and hard before
> trying to implement on my DVR. Is there a way to be "sure [my] particular
> device does properly support SAT mode even though the kernel detects it as
> a device that does not"? I see the linked thread that I'm guessing used to
> tell you how to do that is crossed out, presumably because it no longer
> does?

The strike-through font used to render the "ticket:971#comment:12" link
on the Wiki page simply indicates that Trac ticket #971 now has a status
of "Closed".  That is, that particular Trac ticket is now considered
resolved and will not result in any future changes being made to the
smartmontools programs...  but doesn't imply that the discussion found
in the comments of that ticket is no longer valid, and it's still
definetely worth reading through them.

But unfortunately they won't tell you anything more about the workings
your specific device.  As far as I am aware, the Supported_USB-Devices
wiki page is the only place that attempts to document compatibility
between smartmontools and various USB devices -- and it's very sparsely
populated.

The original reporter of ticket #971 seems to have concluding that that
0bc2:231a bridge chip did have functioning SAT ATA passthrough even in
UAS mode after discussing the issue with a Linux kernel developer (but
unfortunately doesn't give details of that coversation).

>From other Trac tickets and the smartmontools lists, I get the
impression that many others facing this situation instead simply switch
to usb-storage mode and use the devices that way.

(I'm a little surprise that this topic [i.e. the fact that
smartmontools/ATA passthrough doesn't work by default on most recent
Seagate external USB drives] doesn't get raised more often with the
Linux develpers [on the linux-usb mailing list, for example], but I
suppose that most people who used external drives don't care about
SMART, and of those who do care about SMART for those drives, falling
back to usb-storage mode works well enough that they don't bother to
fuss with the issue any further...)


							Nathan


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