Re: HP PSC 1350 cardreader problem + fix, needs new unusal_dev FLAG

[Hans de Goede <j.w.r.degoede@hhs.nl>]

James Bottomley wrote:
> On Sun, 2007-06-10 at 18:43 +0200, Hans de Goede wrote:
>> 1) currently I have decided to add quirk code for this to the usb-storage
>>     driver, as I don't want to polute the generic scsi code with this, but maybe
>>     it would be better to add a quirk for this to the scsi layer?
>> 2) What on earth should I name the flag for this?
> 
> It probably makes the most sense to keep this at the USB layer.  I can't
> see any properly conforming SCSI device having this problem.  Plus the
> command construction is currently a submit hot path for SCSI ... this
> would add an extra check to that path.
> 
>> 3) Currently I just shorten the read / write by one sector. The scsi layer then
>>     notices the 1 sector to short read/write and sends a new command for the
>>     last sector. This works well, but is it ok to depend on the scsi layer
>>     behaving this way?
> 
> Yes, that's behaviour by design.
> 
>> 4) Should I be checking for other READ_X and WRITE_x commands too?
> 
> That depends on USB storage, but I think it currently sets the
> use_10_for_rw flag which forces us only to use READ_10/WRITE_10
> 
> James
> 

Thanks for the quick and thorough answer! I've submitted a pathc for this to 
the usb-storage list.

Regards,

Hans