Re: A question about UAS

[Aaron Dewes <aaron.dewes@web.de>]

> On Sat, Mar 06, 2021 at 06:27:06PM +0100, Aaron Dewes wrote:
>>> On Sat, Mar 06, 2021 at 05:34:32PM +0100, Aaron Dewes wrote:
>>>> Hello!
>>>>
>>>> Sorry if this suggestion/question sounds stupid, I don't have experience
>>>> with the kernel code and this mailing list.
>>>>
>>>> I'm a contributor to Umbrel (getumbrel.com), and we provide a software
>>>> that allows to run a bitcoin node easily, and we've run into many people
>>>> having UAS issues
>>> What specific UAS issues?  And why not just fix those instead?
>> Sorry, I should've been more specific. When I said UAS issues, I meant
>> that we've had many users who used drives that were incompatible with
>> UAS, and that script is our way to detect that and fix it, because the
>> kernel apparently often doesn't detect that, and I think that way would
>> be a way to actually automatically detect such issues.
> The kernel _does_ autodetect drives that don't claim to support uas.
> Are you saying that your users have drives which claim to support uas
> but don't actually support it?  If that's so, can you tell us what
> drives they are so we can put this information into the kernel?

This is what we added to cmdline, but the list was too large, so we had
to remove a few for our latest release:

usb-storage.quirks=152d:1561:u,152d:1576:u,152d:0578:u,125f:a76a:u,04e8:61b6:u,174c:55aa:u,04e8:61f5:u,04e8:4001:u,1058:082a:u,2109:0711:u,152d:0562:u,7825:a2a4:u,04e8:4001:u

I don't remember all the drives, these were mostly reports from users
who had issues.

A few ones I could look up in our commit history:

- JMicron JMS578 and JMS579

- Samsung M3 Portable

- ADATA ED600

- PA023U3

- A SATA-to-USB adapter sold by "BerryBase", a German RPi-related shop

This is on kernel 5.4, so some might have already been added.

To me, it seems like most, if not all devices with the vendor id "152d"
have UAS issues.

> And can you tell us what errors the users encounter?
Either a complete crash & unmount of the connection or really slow
writing speed.
> Also, how can you be sure that the drives don't support uas at all, as
> opposed to supporting uas in general but not a few specific commands?
I'm not sure about that.
>> Currently, drivers/usb/storage/unusual_devs.h disables UAS for a few
>> devices, but autodetecting would be better in my opinion.
> Autodetecting the way you want wouldn't really work very well.  It would
> require the user to plug in the drive and initiate some actiity on it
> which would generate a flurry of errors, so that the kernel could see
> that it should try usb-storage instead.  Then the user would have to
> unplug the drive and plug it in a second time so that usb-storage could
> manage it.
>
> Alan Stern
Oh, I see, then that's not good.

Thank you for your reply!

Aaron Dewes