Another usb umass question...

Scott Long scottl at samsco.org
Sat Feb 24 03:54:42 UTC 2007


M. Warner Losh wrote:
> OK.  I have another umass qustion...
> 
> I have two external USB enclosures that I've been using... One has a
> DVD burner in it and the other has a real disk in it.  I've found that
> I've had some issues.  umass, unpatched, seems to filter out many of
> the SCSI commands that I want to use to burn DVDs and/or run smartmon
> for the disk.  Even with the slowness in usb I see on my amd64 box, it
> still seems to be a faster drive than the ata dvd burner that came
> with the laptop...
> 
> I also know that there are ISSUES with many of the thumb drives which
> is why the filters are in place.
> 
> Is there some kind of middle ground that can accomidate both uses?  Is
> there some automated way of detecting these two different cases?
> 
> Warner

Yes, there is a more intelligent way to handle it, but it requires 
breaking umass into a USB front end and various ATA, MMC, RBC, and SBC 
backends, and/or doing the same in CAM core.

Scott



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