From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Thu, 29 May 2014 15:25:32 -0600 Subject: [U-Boot] [PATCH 1/2] usb: hub: fix power good delay timing In-Reply-To: <1400530878-15956-1-git-send-email-swarren@wwwdotorg.org> References: <1400530878-15956-1-git-send-email-swarren@wwwdotorg.org> Message-ID: <5387A5CC.60509@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 05/19/2014 02:21 PM, Stephen Warren wrote: > From: Stephen Warren > > 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?