Re: [smartmontools-support] Prolific PL2773 USB bridge support

[Andreas M. <an...@us...>]

Hi,

On Thu, Jul 12, 2012 at 07:44:06AM +0200, Christian Franke wrote:
> Andreas Mohr wrote:
> >Any hints as to what JMicron said about pass-through support (SAT or
> >otherwise) of their early (I suppose they're earlier than 30330 etc.)
> >JMF601/JMF602 chipsets?
> 
> No. I got a spec for their USB->SATA/PATA bridges, not for SSD
> controllers with USB 2 interface.

Indeed, that's of course a remarkable difference.


> >Got the 152d:0601 (not even 0602!) here, NOTHING works.
> >Even doing some modification tricks with existing
> >usbjmicron smartmontools source still never manages to succeed.
> >Neither the SAT SCSI command nor the vendor-specific JMicron pass-through
> >SCSI command work, in any way, shape or form.
> >
> >Don't tell me that that chipset's SMART support is SATA-only... ===:-|
> 
> Possibly. The fact that the SATA->Flash layer of the firmware
> supports the SMART feature set does not imply that the USB->SATA
> layer includes an ATA pass-through command.

Right.


> Does it make any sense to access a SSD via USB 2.0 (<= 30MiB/s) ?

Resounding "NO!!". Except for the pathological case of an Acer Aspire
One, SSD version (space-constraint case version) which somehow managed
to defy any and all attempts to get the SSD PCB builtin and at the same
time managing a successful SATA wire connection, too
(SATA wiring probably is awfully signal sensitive for such manual cable
lengths).
Which is why I'm currently forced to running an external USB connection.
OTOH speed with this kind of USB-crippled / device-feature-crippled setup
(the somehow infamous JMF601) still is **MUCH** better than the original
ZIF-based SSD (I had the faster of the two ZIF SSD variants, I believe
Intel-based - until it died horribly).
It is a much newer kernel version, too, though, thus perhaps drastically
improved I/O elevators etc.


> Are you aware of any other tool able to read SMART data from this device?

I should do more research on that (either SATA or USB interfacing
behaviour).


> 
> Thanks,
> Christian

Thank you very much for your clarification on your knowledge of this
device's status! (a JMicron request is currently outstanding - actually
sent from Taiwan at that time ;)). Will keep you updated.

Andreas Mohr