Re: [linux-usb-devel] Genesys USB 2.0 enclosures

[Grant Coady]

On Sun, 4 Sep 2005 14:04:46 -0700, Matthew Dharm <mdharm-kernel@xxxxxxxxxxxxxxxxxx> wrote:

>On Sat, Sep 03, 2005 at 09:53:19PM -0400, Alan Stern wrote:
>> On Sat, 3 Sep 2005, Jan De Luyck wrote:
>> 
>> > I've posted in the past about problems with these enclosures - increasing the 
>> > delay seems to fix it, albeit temporarily. The further you go in using the 
>> > disk in such an enclosure, the higher the udelay() had to be - atleast that's 
>> > what I'm seeing here (I've got two of these now :/ )
>> > 
>> > One permanent fix is adding a powered USB-hub in between the drive enclosures 
>> > and the computer. Since I've done that, I've no longer seen any of the 
>> > problems (i've attached the 'fault' log). Weird but true, since the drives 
>> > come with their own powersupply.
>> > 
>> > Hope this helps anyone in the future running into the same problem.
>> 
>> This one certainly goes into the Bizarro file.
>> 
>> Just out of curiosity -- when you use the powered hub, does the drive work 
>> even if you remove that delay completely?
>
>Aren't USB 2.0 hubs more "intelligent" as part of the requirement to
>support 1.1 and 2.0 devices?  I wonder if it's really a 2.0 drive, and if
>the timing is different enough with the hub to make a difference.

Fixed a USB powered (two USB plugs) Genesys based 2.5" HDD enclosure with 
extra 5V supply bypass capacitors, the HDD was shutting down without loss 
of data with a 'soft' 5V supply.  Now USB drive works everywhere except a 
laptop with a single USB.  HDD uses 700mA, USB is spec'd 500mA per socket.

Some bugs are the hardware :o)

Grant.

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