On Mon, Apr 07, 2008 at 09:05:09AM -0700, David Brownell wrote: > On Monday 07 April 2008, Felipe Balbi wrote: > > I recall having some issues on 100mA devices. During enumeration some > > current spikes a few mAs above 100mA were occuring and we couldn't > > enumerate the device due to vbus_err interrupt. > > Yeah, I think the Mentor core is unduly sensitive to voltage > fluctuation during enumeration. There's supposed to be about > 100 msec before VBUS must stabilize ... but the silicon doesn't > seem to accept routine instabilities in that period, and then > reports inappropriate VBUS errors. > > > > If you check drivers/usb/musb/tusb6010.c you'll see that we've > > implemented a retry condition for those cases. The same retry can > > be found in musb_core.c > > The DaVinci support needed the same kind of logic. All in > all this is painful stuff to sort out, and it seems that > each platform rediscovers it. It would be better if the > silicon itself weren't fighting back so hard... Good point. -- Best Regards, Felipe Balbi me@xxxxxxxxxxxxxxx http://blog.felipebalbi.com -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
