From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Tue, 2 Apr 2013 12:33:20 +0200 Subject: [U-Boot] [PATCH 2/7] usb: hub: Conditionally power on usb's root-hub ports In-Reply-To: References: <1364376543-7526-1-git-send-email-gautam.vivek@samsung.com> <201304021209.08480.marex@denx.de> Message-ID: <201304021233.20828.marex@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Dear Vivek Gautam, > Hi, > > On Tue, Apr 2, 2013 at 3:39 PM, Marek Vasut wrote: > > Dear Vivek Gautam, > > > >> Hi Marek, > >> > >> Adding CC: Amarendra > >> > >> On Thu, Mar 28, 2013 at 7:58 PM, Marek Vasut wrote: > >> > Dear Vivek Gautam, > >> > > >> >> Power on root hubs' ports only when they are not yet powered on. > >> >> Its seen with USB 3.0 ports that they are powered on after > >> >> a H/W reset, as also reflected in XHCI spec (sec 4.3): > >> >> "After a Chip Hardware Reset, HCRST, or commanded to the > >> >> PLS = RxDetect state, all Root Hub ports shall be in Disconnected > >> >> state, i.e. the port is powered on (PP = 1)" > >> >> > >> >> Signed-off-by: Amar > >> >> Signed-off-by: Vivek Gautam > >> > > >> > Just wondering if we shouldn't power-cycle all the ports instead -- > >> > aka. turn them off and then turn all of them on again. > >> > >> Hmm, seems like a fine idea. > >> Will it be fine to power-cycle even EHCI ports too ? > >> Or we just check if ports are already powered-up (as in XHCI) we > >> power-cycle them. > > > > EHCI as well, all of them without differentiating the type. Why not , do > > you see a problem ? > > Not of course, will amend this accordingly. Sounds great! Thank you! Best regards, Marek Vasut