Re: Unreliable USB3 with NEC uPD720200 and Delock Cardreader

[Sarah Sharp <sarah.a.sharp@linux.intel.com>]

On Wed, Nov 28, 2012 at 02:54:06PM -0800, Sarah Sharp wrote:
> On Mon, Nov 26, 2012 at 10:48:03PM +0100, Bjørn Mork wrote:
> > Sarah Sharp <sarah.a.sharp@linux.intel.com> writes:
> > 
> > > It looks like both Ulrich and Andrew have the same issue.  I also have a
> > > Lenovo x220, and I confirmed that when I turn on PCI runtime suspend,
> > > the NEC host controller does not report port status changes when a new
> > > USB device is plugged in.
> > >
> > > I'm running 3.6.7, and I'm pretty sure that runtime suspend worked for
> > > the NEC host on some older kernel.  I don't think the NEC host went into
> > > D3cold on that kernel, though.  Is there a way to disable D3cold and
> > > just use D3hot instead?
> > 
> > Yes, you have /sys/bus/pci/devices/.../d3cold_allowed
> > See Documentation/ABI/testing/sysfs-bus-pci
> > 
> > If this really is a problem with the D3cold support that went into 3.6
> > then I guess you should include Huang Ying in the discussions as well
> > (CCed).
> 
> Turning off D3 cold didn't help.  Once the PCI device is suspended,
> connect events do not generate an interrupt.
> 
> I'll go see if I can figure out which kernel this worked on and bisect.

Wakeup from D3 works fine on the 3.5.0 kernel, but fails on 3.6.2.  I
haven't fully bisected yet.

In debugging, I found that if you only enable runtime suspend for the
NEC host controller, the host successfully comes out of D3 when you plug
in a USB device.  However, if you enable runtime PM for the parent PCIe root
port, it stops working.  Disabling D3cold for both devices did not help.

It looks like a PCI issue, so what sort of debugging info do you need
from me?

Sarah Sharp