[pvrusb2] Module ehci-hcd may prevent pvrusb2 reconnect

[Mike Isely]

On Thu, 27 Mar 2008, roger wrote:

> Found a bug, if the pvrusb2 device is disconnected via power cable and
> then plugged back in with the ehci-hcd module still loaded, the device
> may fail initializing and the system logger will only show:
> 
> Mar 27 19:59:07 pvrusb2: unregistered device video0 [mpeg]
> Mar 27 19:59:07 pvrusb2: unregistered device radio0 [mpeg]
> Mar 27 19:59:07 msp3400 1-0040: chip reset failed
> 
> Or, you may only get a one or two line notice stating the pvrusb2 has
> been plugged in (with no device initialization).
> 
> 
> A work around, compile ehci-hcd as module and manually reload
> (rmmd/modprobe) the ehci-hcd module.  Unloading the pvrusb2 module or
> any of it's dependents (msp3400) doesn't seem to be need for the pvrusb2
> to initialize.  Matter of fact, just removing the ehci-hcd module (ie.
> rmmod ehci-hcd) without even loading the ehci-hcd module will
> automatically allow the pvrusb2 device to initialize.
> 
> This may have been a long standing issue for the past year or more.
> 

Really?  I'm surprised.  This is the first report of a problem like this 
that I've seen.

Reloading the USB host controller driver is going to have the same 
effect as re-plugging in everything that was attached to the 
controller's USB ports.  So of course the pvrusb2 device will be 
re-enumerated by this action.

When a pvrusb2 device is plugged in, you should ALSO see a message like 
this:

usb 5-2: new high speed USB device using ehci_hcd and address 6

(with different address values of course)

That message comes directly from the USB core not the pvrusb2 driver.  
If it doesn't appear, then the USB core is simply failing to spot the 
newly plugged in device - and there is very very little that a USB 
device could do to prevent itself from being at least seen by the USB 
controller (detection is done via a resistor connected between ground 
and one of the USB data wires).  Said another way, if you are having 
this problem, then (1) it can't be from the pvrusb2 driver, and (2) it 
can't be from the pvrusb2 hardware either.  Sounds more likely that 
you've got general USB issues here.

I routinely power cycle plugged in devices here.  Reinitialization works 
every time.  Are you SURE about this?

  -Mike


-- 

Mike Isely
isely @ pobox (dot) com
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