From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-path: Date: Wed, 17 Oct 2018 18:03:35 -0700 From: Nicolin Chen To: Guenter Roeck Cc: jdelvare@suse.com, linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/5] hwmon: (ina3221) Return -ENODATA for two alarms attributes Message-ID: <20181018010335.GA15221@Asurada-Nvidia.nvidia.com> References: <20181017012426.26958-1-nicoleotsuka@gmail.com> <20181017012426.26958-3-nicoleotsuka@gmail.com> <20181017194605.GB6812@roeck-us.net> <20181017203917.GB15941@Asurada-Nvidia.nvidia.com> <20181017211426.GA10990@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181017211426.GA10990@roeck-us.net> List-ID: On Wed, Oct 17, 2018 at 02:14:26PM -0700, Guenter Roeck wrote: > On Wed, Oct 17, 2018 at 01:39:17PM -0700, Nicolin Chen wrote: > > On Wed, Oct 17, 2018 at 12:46:05PM -0700, Guenter Roeck wrote: > > > On Tue, Oct 16, 2018 at 06:24:23PM -0700, Nicolin Chen wrote: > > > > There is nothing critically wrong to read these two attributes > > > > without having a is_enabled() check at this point. But reading > > > > the MASK_ENABLE register would clear the CVRF bit according to > > > > the datasheet. So it'd be safer to fence for disabled channels > > > > in order to add pm runtime feature. > > > > > > > > Signed-off-by: Nicolin Chen > > > > --- > > > > drivers/hwmon/ina3221.c | 2 ++ > > > > 1 file changed, 2 insertions(+) > > > > > > > > diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c > > > > index d61688f04594..3e98b59108ee 100644 > > > > --- a/drivers/hwmon/ina3221.c > > > > +++ b/drivers/hwmon/ina3221.c > > > > @@ -200,6 +200,8 @@ static int ina3221_read_curr(struct device *dev, u32 attr, > > > > return 0; > > > > case hwmon_curr_crit_alarm: > > > > case hwmon_curr_max_alarm: > > > > + if (!ina3221_is_enabled(ina, channel)) > > > > + return -ENODATA; > > > > > > Makes sense, but can you check what the sensors command does with this ? > > > > Not quite understanding the question. Do you mean the user case > > causing the race condition -- wiping out the CVRF bit? > > > No. Question is what the "sensors" command reports if reading the alarm > attribute returns -ENODATA. If it reports an error, we would have a regression. I see. I will return 0 instead. Thanks Nicolin