From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heikki Krogerus Subject: Re: [PATCH v2 3/8] core: platform: wakeup the parent before trying any driver operations Date: Tue, 26 May 2015 16:28:14 +0300 Message-ID: <20150526132814.GA12719@kuha.fi.intel.com> References: <1432570172-86963-4-git-send-email-andriy.shevchenko@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Alan Stern Cc: Andy Shevchenko , "Rafael J. Wysocki" , 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, Jarkko Nikula List-Id: linux-acpi@vger.kernel.org On Mon, May 25, 2015 at 01:36:43PM -0400, Alan Stern wrote: > On Mon, 25 May 2015, Andy Shevchenko wrote: > > > From: Heikki Krogerus > > > > If the parent is still suspended when a driver probe, > > remove or shutdown is attempted, the result may be a > > 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 using driver probe, remove or shutdown. > > > > Signed-off-by: Heikki Krogerus > > Signed-off-by: Andy Shevchenko > > --- > > drivers/base/platform.c | 21 ++++++++++++++++++++- > > Why make the changes here rather than in dd.c? Is there something > special about platform devices? There isn't. That would definitely be better. Thanks Alan, -- heikki