On Fri, 2003-05-30 at 18:17, Greg KH wrote:
> On Fri, May 30, 2003 at 04:56:13PM +0100, Martin Evans wrote:
> > 
> > There are no timeout or other error messages from the usb_control_msg
> > statement in the driver. As far as I can tell, the function returns
> > normally with a zero exit status.
> 
> But it looks like the message isn't getting out to the device?  Any
> chance you need to have a self-powered hub in order to get enough power
> out to the pl2303 devices to all be able to signal a break?
> 

They are on self powered hubs. The main ones are 7 port hubs. However, I
do have another 4 port hub (again self powered) lying around and that
has similar problems when 4 devices are attached.


> The fact that this happens when you start to have a lot of devices all
> attached to a single hub lends itself to being a hardware problem...
> 

If that was the case I would see data loss during ordinary serial
transfers, there is no such data loss... ordinary characters get through
OK. Also I'm curious as to why the usb_control_msg function returns 0.
Would that fail with a timeout or something if there was not enough
power to see the device?


Thanks,
Martin.

-- 
-- Dr MDT Evans, Computing Services, Queen Mary, University of London



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