From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758021AbdELRq1 (ORCPT ); Fri, 12 May 2017 13:46:27 -0400 Received: from muru.com ([72.249.23.125]:47506 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751681AbdELRqZ (ORCPT ); Fri, 12 May 2017 13:46:25 -0400 Date: Fri, 12 May 2017 10:46:21 -0700 From: Tony Lindgren To: Bin Liu , Moreno Bartalucci , Lars Melin , "linux-omap@vger.kernel.org" , "linux-usb@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Alessio Igor Bogani Subject: Re: [PATCH] usb-musb: keep VBUS on when device is disconnected Message-ID: <20170512174621.GJ3489@atomide.com> References: <20170511193810.GX3489@atomide.com> <20170511200220.GH7154@uda0271908> <20170511202306.GY3489@atomide.com> <20170511204406.GI7154@uda0271908> <20170511210628.GA3489@atomide.com> <20170512134042.GK7154@uda0271908> <20170512145849.GE3489@atomide.com> <20170512152144.GA651@uda0271908> <20170512172134.GI3489@atomide.com> <20170512174026.GB651@uda0271908> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170512174026.GB651@uda0271908> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Bin Liu [170512 10:43]: > On Fri, May 12, 2017 at 10:21:35AM -0700, Tony Lindgren wrote: > > * Bin Liu [170512 08:24]: > > > On Fri, May 12, 2017 at 07:58:49AM -0700, Tony Lindgren wrote: > > > > OK. No better ideas except I think we should probably have a separate > > > > timer for keeping VBUS on after state changes eventually. > > > > > > Currently with the patch below, VBUS is constantly on for host-only > > > mode, and this is what we want. Why we need a separate timer? No one > > > cuts VBUs now for host-only mode. > > > > Oh I was just thinking what we might want to do in the future if > > we want to cut off VBUS when no devices are connected. If we have > > Okay, I see. But I don't think we will ever want to turn off VBUS when > no devices attached for host-only mode. Any other controllers do this? > > Turning off VBUS doesn't save us much, because it comes from an external > power rail, and no one consumes it when no devices are attached. > > I believe keeping the controller idle as what we have now is sufficient. OK fine with me. Regards, Tony