On Tue, 13 May 2003, Helge Hafting wrote:
> On Tue, May 13, 2003 at 05:35:47PM -0400, Alan Stern wrote:
> > My take is that wakeup_hc() is getting called whenever some stray signal
> > causes the device to generate an interrupt, and then a little while later
> > the stall timer routine calls suspend_hc() since nothing is active. The
> > interrupts are probably indistinguishable from what you would get if a new
> > device really had just been attached to the bus.
> >
> Could this also happen if the USB interrupt is shared?
> The other device interrupts, and the kernel calls into
> usb interrupt routine just in case USB has some data too?
Yes, it certainly could. The other part of the problem, which I failed to
mention, is that the Resume-Detect bit in the USB controller's status
register is set. wakeup_hc() gets called only if that bit is set, and the
bit is supposed to be set only if some device attached to the USB bus has
requested a wakeup (also known as "resume"). If there's nothing on the
bus, the controller shouldn't indicate that a resume was detected.
Alan Stern
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This archive was generated by hypermail 2b29 : Thu May 15 2003 - 22:00:48 EST