From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH v3 3/8] Driver core: wakeup the parent device before trying probe Date: Wed, 10 Jun 2015 17:02:21 +0300 Message-ID: <1433944941.26331.119.camel@linux.intel.com> References: <1433170082-117462-1-git-send-email-andriy.shevchenko@linux.intel.com> <1433170082-117462-4-git-send-email-andriy.shevchenko@linux.intel.com> <6646339.jahMH2QKDR@vostro.rjw.lan> <3252449.XN2pzxrAPQ@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3252449.XN2pzxrAPQ@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, Greg Kroah-Hartman , Vinod Koul , Lee Jones , Andrew Morton , Mika Westerberg , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Heikki Krogerus , Jarkko Nikula , "Wysocki, Rafael J" , Mike Turquette List-Id: linux-pm@vger.kernel.org On Wed, 2015-06-10 at 02:08 +0200, Rafael J. Wysocki wrote: > On Tuesday, June 09, 2015 01:42:00 AM Rafael J. Wysocki wrote: > > On Monday, June 01, 2015 05:47:57 PM Andy Shevchenko wrote: > > > From: Heikki Krogerus > > > > > > If the parent is still suspended when driver probe is > > > attempted, the result may be failure. > > > > > > For example, if the parent is a PCI MFD device that has been > > > suspended when we try to probe our device, any register > > > reads will return 0xffffffff. > > > > > > To fix the problem, making sure the parent is always awake > > > before attempting driver probe. [] > Actually, something like the below should work too (the bumping up of the > parent's usage counter before the loop will keep it in the runtime-active > state throughout the loop). It works. Thanks for the patch. We incorporate it instead of the previous Heikki's patch into v4. -- Andy Shevchenko Intel Finland Oy