[smartmontools-support] Unbreaking Seagate UAS smart reporting at the kernel level

[Nathan Stratton Treadway]

(Sorry, I missed the message when you first sent it.  I will try to
write a longer response later, but here is a quick initial reply.)

[Note that I'm not part of the Smartmontools project, other than as a
user -- and someone who was confused when my external Seagate drive
inexplicably could not be accessed by hdparm/smartmontools on my newer
computer but could just fine an older one... and ended up consolidating
what I was able to track down in my research into that wiki page...]


On Mon, Apr 26, 2021 at 10:47:45 +0200, Hans de Goede wrote:
> My reasoning here is that having drives not hang (possibly while a
> filesystem is mounted, causing fs damage) is more important then
> having working SMART support. Note I'm not saying that SMART is not
> important, I'm merly saying that having the basic storage functionality
> of the drive working is even more important.

Fair enough. :) 

> 
> Still it would be good if we can both have our cake and eat it.
> 
> So for now the plan is to add a new US_FL_ATA_1X_OK (1) flag to the set
> of flags used by the usb_storage and uas drivers and set that for known
> to work Seagate models. Which would product id 0xab03 from the starter of

In general it does sounds good to have the ability to better manage the
whitelisting/blacklisting of specific drives (and especially for people
who have one of the "it actually works" Seagates).

However, from the standpoint of the smartmontools/hdparm commands, what
would be even nicer is some way to get SAT passthrough to work even when
the drive is being used in UAS mode.  

The questions that came to my mind back when I was looking into this (but
didn't find the answers at that time) were:
  1) why does SAT pass-through work in usb-storage mode but not UAS?, and

  2) would there be a way for the UAS driver to somehow drop back to
     some usb-storage-like USB communication in order to send the
     SAT-pass through command to the drive?

(Note that in this context the smartmontool/hdparm command are "one
shot" commands involving a limited amount of data, so presumably the
speed/etc. benefits of UAS don't matter for those specific
transactions.)
 

							Nathan


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