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[85.230.190.116]) by smtp.gmail.com with ESMTPSA id t22sm4189527lje.58.2019.06.05.00.56.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Jun 2019 00:56:59 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.91) (envelope-from ) id 1hYQn2-00063e-Gt; Wed, 05 Jun 2019 09:56:57 +0200 Date: Wed, 5 Jun 2019 09:56:56 +0200 From: Johan Hovold To: Lee Jones Cc: Bjorn Andersson , balbi@kernel.org, wsa+renesas@sang-engineering.com, gregkh@linuxfoundation.org, linus.walleij@linaro.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, david.brown@linaro.org, alokc@codeaurora.org, kramasub@codeaurora.org, linux-i2c@vger.kernel.org, linux-gpio@vger.kernel.org, linux-arm-msm@vger.kernel.org, andy.gross@linaro.org, jlhugo@gmail.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/8] i2c: i2c-qcom-geni: Signify successful driver probe Message-ID: <20190605075656.GC29637@localhost> References: <20190604104455.8877-1-lee.jones@linaro.org> <20190604104455.8877-2-lee.jones@linaro.org> <20190605062020.GL22737@tuxbook-pro> <20190605071625.GK4797@dell> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190605071625.GK4797@dell> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Wed, Jun 05, 2019 at 08:16:25AM +0100, Lee Jones wrote: > On Tue, 04 Jun 2019, Bjorn Andersson wrote: > > > On Tue 04 Jun 03:44 PDT 2019, Lee Jones wrote: > > > > > The Qualcomm Geni I2C driver currently probes silently which can be > > > confusing when debugging potential issues. Add a low level (INFO) > > > print when each I2C controller is successfully initially set-up. > > > > > > Signed-off-by: Lee Jones > > > --- > > > drivers/i2c/busses/i2c-qcom-geni.c | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c > > > index 0fa93b448e8d..e27466d77767 100644 > > > --- a/drivers/i2c/busses/i2c-qcom-geni.c > > > +++ b/drivers/i2c/busses/i2c-qcom-geni.c > > > @@ -598,6 +598,8 @@ static int geni_i2c_probe(struct platform_device *pdev) > > > return ret; > > > } > > > > > > + dev_info(&pdev->dev, "Geni-I2C adaptor successfully added\n"); > > > + > > > > I would prefer that we do not add such prints, as it would be to accept > > the downstream behaviour of spamming the log to the point where no one > > will ever look through it. > > We should be able to find a middle ground. Spamming the log with all > sorts of device specific information/debug is obviously not > constructive, but a single liner to advertise that an important > device/controller has been successfully initialised is more helpful > than it is hinderous. > > This print was added due to the silent initialisation costing me > several hours of debugging ACPI device/driver code (albeit learning a > lot about ACPI as I go) just to find out that it was already doing the > right thing - just very quietly. No, we don't add noise like this to the logs just because it may be useful while debugging. Even one-liners add up. There are plenty of options for debugging already ranging from adding a temporary dev_info() to the probe function in question to using dynamic debugging to have driver core log every successful probe. And in this case you say the driver was in fact already bound; that can easily be verified through sysfs too in case things aren't behaving the way you expect. Johan