Re: omap: USB host disconnects connecting a device through USB HUB

[Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>]

On Thu, Apr 07, 2011 at 11:03:38PM +0200, Enric Balletbò i Serra wrote:
> Hi,
> 
> 2011/4/7 Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>:
> > On Thu, 7 Apr 2011, Enric Balletbò i Serra wrote:
> >
> >> Hi all,
> >>
> >> I'm experimenting some issues with USB on IGEP v2 board, in certain
> >> cases I've an USB disconnect when I plug a device. For me it fails
> >> with kernel 2.6.35 but I think it also affect newer kernel, the issue
> >> is easy to reproduce following these steps:
> >>
> >> 1. Power up the board (without any device connected )
> >>
> >> 2. When kernel is up, connect a powered USB HUB 2.0 to the USB host
> >> port, kernel shows,
> >>
> >> usb 1-1: new high speed USB device using ehci-omap and address 2
> >> usb 1-1: New USB device found, idVendor=05e3, idProduct=0608
> >> usb 1-1: New USB device strings: Mfr=0, Product=1, SerialNumber=0
> >> usb 1-1: Product: USB2.0 Hub
> >> hub 1-1:1.0: USB hub found
> >> hub 1-1:1.0: 4 ports detected
> >> usb 1-1.4: new high speed USB device using ehci-omap and address 3
> >> usb 1-1.4: New USB device found, idVendor=05e3, idProduct=0608
> >> usb 1-1.4: New USB device strings: Mfr=0, Product=1, SerialNumber=0
> >> usb 1-1.4: Product: USB2.0 Hub
> >> hub 1-1.4:1.0: USB hub found
> >> hub 1-1.4:1.0: 4 ports detected
> >>
> >> 3. Then if I connect a device (for example a pendrive) to the HUB I
> >> get USB disconnect message
> >>
> >> usb 1-1: USB disconnect, address 2
> >> usb 1-1.4: USB disconnect, address 3
> >>
> >> OTOH, it works without problem
> >>   1. if power up the board with the USB HUB connected to the USB Host
> >> port and the device connected to the USB hub.
> >>   2. if after kernel is up, connect the USB HUB + device to the USB Host port
> >>
> >> Anyone is experimenting something like this with other OMAP3-based boards ?
> >
> > At first glance, it looks like a power-related issue.  Current inrush
> > when the device is plugged in, or something like that.
> >
> > What happens if you attach the hub and pendrive to a standard PC?
> >
> 
> With standard PC works as expected, would be possible a problem with
> omap-ehci driver ? Maybe Felipe can give some light ?

Maybe PM is kicking in and turning off the clocks. Donno. What if you
use function tracer so we know the last called function before the
problem ? Just filter the call to *hci*.

-- 
balbi
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