[U-Boot] [PATCH 1/2] usb: hub: fix power good delay timing

Marek Vasut marex at denx.de
Sun Jun 1 19:20:18 CEST 2014


On Thursday, May 29, 2014 at 11:25:32 PM, Stephen Warren wrote:
> On 05/19/2014 02:21 PM, Stephen Warren wrote:
> > From: Stephen Warren <swarren at nvidia.com>
> > 
> > usb_hub_power_on() currently waits for the maximum of (a) the hub port's
> > power output to become good, (b) the max time the USB specification
> > allows a device to take to connect.
> > 
> > However, these two operations must occur in series rather than in
> > parallel. First, the power supply ramps up to the level required to
> > power the USB device, and then the device may take a certain amount of
> > time to connect (assert D+/D- pullups).
> > 
> > Related, the maximum time that a device has to assert pullups is 1s not
> > 100ms.
> > 
> > This is explained in "Connect Timing ECN.pdf", itself part of
> > usb_20_042814.zip from www.usb.org.
> 
> Marek, does this series look OK?

Applied both, thanks!

Best regards,
Marek Vasut


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