From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754782AbcIIT10 (ORCPT ); Fri, 9 Sep 2016 15:27:26 -0400 Received: from galahad.ideasonboard.com ([185.26.127.97]:59560 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754164AbcIIT1W (ORCPT ); Fri, 9 Sep 2016 15:27:22 -0400 From: Laurent Pinchart To: Andreas Kemnade Cc: Bin Liu , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, Tony Lindgren , letux-kernel@openphoenux.org Subject: Re: [v2] musb: omap2430: do not assume balanced enable()/disable() Date: Fri, 09 Sep 2016 22:27:56 +0300 Message-ID: <1946895.vi37Pmm05X@avalon> User-Agent: KMail/4.14.10 (Linux/4.4.6-gentoo; KDE/4.14.20; x86_64; ; ) In-Reply-To: <1470238731-32358-1-git-send-email-andreas@kemnade.info> References: <1470238731-32358-1-git-send-email-andreas@kemnade.info> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andreas, Thank you for the patch. On Wednesday 03 Aug 2016 17:38:51 Andreas Kemnade wrote: > The code assumes that omap2430_musb_enable() and > omap2430_musb_disable() are called in a balanced way. > That fact is broken by the fact that musb_init_controller() calls > musb_platform_disable() to switch from unknown state to off state > on initialisation. > > That means that phy_power_off() is called first so that > phy->power_count gets -1 and the phy is not enabled on phy_power_on(). > So when usb gadget is started the phy is not powered on. > Depending on the phy used that caused various problems. > Besides of causing usb problems, that can also have side effects. > > In the case of using the phy_twl4030, that prevents also charging > the battery via usb (using twl4030_charger) and so makes further > kernel debugging hard. > The problem was seen with 4.7 on an openphoenux gta04. It has a DM3730 > SoC and a TPS65950 companion. phy->power never became 1 > and so the usb did get powered on. > > The patch prevents phy_power_off() from being called when > it is already off. > > Signed-off-by: Andreas Kemnade This fixes USB gadget operation on the Panda board. Fixes: a83e17d0f73b ("usb: musb: Improve PM runtime and phy handling for 2430 glue layer") Tested-by: Laurent Pinchart > --- > changes in v2: > improved commit message > > drivers/usb/musb/omap2430.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c > index 0b4cec9..c1a2b7b 100644 > --- a/drivers/usb/musb/omap2430.c > +++ b/drivers/usb/musb/omap2430.c > @@ -413,9 +413,10 @@ static void omap2430_musb_disable(struct musb *musb) > struct device *dev = musb->controller; > struct omap2430_glue *glue = dev_get_drvdata(dev->parent); > > - if (!WARN_ON(!musb->phy)) > - phy_power_off(musb->phy); > - > + if (glue->enabled) { > + if (!WARN_ON(!musb->phy)) > + phy_power_off(musb->phy); > + } > if (glue->status != MUSB_UNKNOWN) > omap_control_usb_set_mode(glue->control_otghs, > USB_MODE_DISCONNECT); -- Regards, Laurent Pinchart