Re: System hangs when using USB 3.0 HD with on Ubuntu

[Mark Lord <kernel@teksavvy.com>]

On 07/04/10 03:18 PM, Alan Stern wrote:
> On Wed, 7 Apr 2010, Mark Lord wrote:
>
>> Errr.. yes and no.
>>
>> Yes, because nobody else is likely to do anything about it,
>> so I will work around the hardware bug by updating hdparm.
>>
>> But no, there's no funky missing data length issue there.
>> Just a bridge chip that doesn't understand ATA_16 commands.
>
> Did you look at this comment and the following one:
>
> https://bugs.launchpad.net/ubuntu/+source/linux-fsl-imx51/+bug/431963#25
>
> Is the engineer from Genesys Logic totally off-base?
..

Yes.  As discussed already, there is *no* sector count parameter
for the (S)ATA "IDENTIFY" command.  Other USB/SATA bridges handle
this correctly in SAT mode, just not this specific model.

No big deal, we'll work around it.
It's low priority for me, though.

I do have a pre-release HDPARM that uses ATA_12 for IDENTIFY,
as this is reported to work on this hardware, even though it is
otherwise _identical_ to the command issue via ATA_16.
That's another indication of a buggy/inconsistent bridge chip.

And I've also added a sector count of "1" to hdparm's IDENTIFY
commands.  Properly implemented hardware/software will just ignore it
as usual, but this bridge might benefit from it.

Anyone want to give this second update a try?

Thanks