From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: A potential broken at platform driver? Date: Tue, 4 Jun 2019 16:28:37 +0200 Message-ID: <20190604142837.GB28355@kroah.com> References: <1559074833-1325-1-git-send-email-richard.gong@linux.intel.com> <1559074833-1325-3-git-send-email-richard.gong@linux.intel.com> <20190528232224.GA29225@kroah.com> <1e3b5447-b776-f929-bca6-306f90ac0856@linux.intel.com> <20190603180255.GA18054@kroah.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: Richard Gong Cc: robh+dt@kernel.org, mark.rutland@arm.com, dinguyen@kernel.org, atull@kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, sen.li@intel.com, Richard Gong List-Id: devicetree@vger.kernel.org On Mon, Jun 03, 2019 at 06:08:37PM -0500, Richard Gong wrote: > Hi Greg, > > On 6/3/19 1:02 PM, Greg KH wrote: > > On Mon, Jun 03, 2019 at 10:57:18AM -0500, Richard Gong wrote: > > > > > > Hi Greg, > > > > > > Following your suggestion, I replaced devm_device_add_groups() with .group = > > > rus_groups in my version #4 submission. But I found out that RSU driver > > > outputs the garbage data if I use .group = rsu_groups. > > > > What is "garbage"? > I mean incorrect status info. > > > > > > To make RSU driver work properly, I have to revert the change at version #4 > > > and use devm_device_add_groups() again. Sorry, I didn't catch this problem > > > early. > > > > > > I did some debug & below are captured log, you can see priv pointer get > > > messed at current_image_show(). I am not sure if something related to > > > platform driver work properly. I attach my debug patch in this mail. > > > > > > 1. Using .groups = rsu_groups, > > > > > > [ 1.191115] *** rsu_status_callback: > > > [ 1.194782] res->a1=2000000 > > > [ 1.197588] res->a1=0 > > > [ 1.199865] res->a2=0 > > > [ 1.202150] res->a3=0 > > > [ 1.204433] priv=0xffff80007aa28e80 > > > [ 1.207933] version=0, state=0, current_image=2000000, fail_image=0, > > > error_location=0, error_details=0 > > > [ 1.217249] *** stratix10_rsu_probe: priv=0xffff80007aa28e80 > > > root@stratix10:/sys/bus/platform/drivers/stratix10-rsu# cat current_image > > > [ 38.849341] *** current_image_show: priv=0xffff80007aa28d00 > > > ... output garbage data > > > priv pointer got changed > > > > I don't understand this, sorry. Are you sure you are actually using the > > correct pointer to your device? > > > I think so. > > The dev pointer at current_image_show() should points to RSU device, but it > seems point to driver_private if I use .group = rsU_groups. As a result I > can't get the priv pointer properly at current_image_show(). It points to the driver kobject, not the device kobject. So that's the issue here. See the patch that I just posted for a potential fix for this. thanks, greg k-h