Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752516AbaLTV0k (ORCPT ); Sat, 20 Dec 2014 16:26:40 -0500 Received: from mga03.intel.com ([134.134.136.65]:18255 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751821AbaLTV0i (ORCPT ); Sat, 20 Dec 2014 16:26:38 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,615,1413270000"; d="scan'208";a="627128624" Message-ID: <1419110796.2843.6.camel@spandruv-hsb-test> Subject: Re: [RFC PATCH] iio: ak8975: Make sure chipset is always initialized From: Srinivas Pandruvada To: Daniel Baluta Cc: Hartmut Knaack , Jonathan Cameron , Lars-Peter Clausen , Peter Meerwald , gwendal@chromium.org, beomho.seo@samsung.com, "linux-iio@vger.kernel.org" , Linux Kernel Mailing List , "octavian.purdila@intel.com" Date: Sat, 20 Dec 2014 13:26:36 -0800 In-Reply-To: References: <1418923002-901-1-git-send-email-daniel.baluta@intel.com> <5494A3D6.60607@gmx.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2014-12-20 at 00:25 +0200, Daniel Baluta wrote: > On Sat, Dec 20, 2014 at 12:16 AM, Hartmut Knaack wrote: > > Daniel Baluta schrieb am 18.12.2014 um 18:16: > >> When using ACPI, if acpi_match_device fails then chipset enum will be > >> uninitialized and &ak_def_array[chipset] will point to some bad address. > >> I am missing something. You are enumerated over i2c device, which was created from ACPI PNP resource. There is a valid handle or and the device has an ACPI companion at the least. If this failing, I have to check the code for acpi i2c. Can you check why this check failed? We may have bug in i2c handling. Thanks, Srinivas > >> This fixes the following compilation warning: > >> > >> drivers/iio/magnetometer/ak8975.c: In function ‘ak8975_probe’: > >> drivers/iio/magnetometer/ak8975.c:788:14: warning: ‘chipset’ may be used > >> uninitialized in this function [-Wmaybe-uninitialized] > >> data->def =ak_def_array[chipset]; > >> > >> Reported-by: Octavian Purdila > >> Signed-off-by: Daniel Baluta > >> --- > >> This is a RFC because while I'm pretty sure that chipset should be initialized > >> with AK_MAX_TYPE in ak8975_match_acpi_device, I am not sure if we can live with > >> a NULL return value of ak8975_match_acpi_device. Current implementation ignores > >> return value of ak8975_match_acpi_device. > > This seems to be the actual problem: these _match_acpi_device functions return > > NULL on failure, and this should be checked for. > > Ok, so this would acceptable? > > diff --git a/drivers/iio/magnetometer/ak8975.c > b/drivers/iio/magnetometer/ak8975.c > index 0d10a4b..68d99e9 100644 > --- a/drivers/iio/magnetometer/ak8975.c > +++ b/drivers/iio/magnetometer/ak8975.c > @@ -776,8 +776,9 @@ static int ak8975_probe(struct i2c_client *client, > name = id->name; > } else if (ACPI_HANDLE(&client->dev)) > name = ak8975_match_acpi_device(&client->dev, &chipset); > - else > - return -ENOSYS; > + > + if (!name) > + return -ENODEV; > > > I still have some doubts about return code in case of error. > > For ak8975 we use -ENOSYS, but for kxcjk-1013 we use -ENODEV. > > I will send a patch after we clear this out. > > thanks, > Daniel. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/