On Fri, Feb 13, 2015 at 03:07:43PM -0600, Felipe Balbi wrote: > Every USB Host controller should use this new > macro to define for how long resume signalling > should be driven on the bus. > > Currently, almost every single USB controller > is using a 20ms timeout for resume signalling. > > That's problematic for two reasons: > > a) sometimes that 20ms timer expires a little > before 20ms, which makes us fail certification > > b) some (many) devices actually need more than > 20ms resume signalling. > > Sure, in case of (b) we can state that the device > is against the USB spec, but the fact is that > we have no control over which device the certification > lab will use. We also have no control over which host > they will use. Most likely they'll be using a Windows > PC which, again, we have no control over how that > USB stack is written and how long resume signalling > they are using. > > At the end of the day, we must make sure Linux passes > electrical compliance when working as Host or as Device > and currently we don't pass compliance as host because > we're driving resume signallig for exactly 20ms and > that confuses certification test setup resulting in > Certification failure. > > Signed-off-by: Felipe Balbi <ba...@ti.com> > ---
btw, the electrical test bug was reproduced with both MUSB and XHCI (AM335x BeagleBone Black and AM437x Starter Kit) -- balbi
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