From: Lee Jones <lee.jones@linaro.org>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>,
balbi@kernel.org, wsa+renesas@sang-engineering.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Walleij <linus.walleij@linaro.org>,
linux-usb <linux-usb@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
David Brown <david.brown@linaro.org>,
alokc@codeaurora.org, kramasub@codeaurora.org,
linux-i2c <linux-i2c@vger.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Andy Gross <andy.gross@linaro.org>,
Jeffrey Hugo <jlhugo@gmail.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 2/8] i2c: i2c-qcom-geni: Signify successful driver probe
Date: Wed, 5 Jun 2019 09:23:27 +0100 [thread overview]
Message-ID: <20190605082327.GN4797@dell> (raw)
In-Reply-To: <CAKv+Gu_YcdePUkkCGdP5DC9rxCUAshgOzU32pViAp2CbmAaJuw@mail.gmail.com>
On Wed, 05 Jun 2019, Ard Biesheuvel wrote:
> On Wed, 5 Jun 2019 at 09:16, Lee Jones <lee.jones@linaro.org> 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 <lee.jones@linaro.org>
> > > > ---
> > > > 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.
> >
>
> I agree.
>
> There are numerous EHCI drivers IIRC which, if compiled in,
> unconditionally print some blurb, whether you have the hardware or
> not, which is pretty annoying.
>
> In this case, however, having a single line per successfully probed
> device (containing the dev_name and perhaps the MMIO base address or
> some other identifying feature) is pretty useful, and shouldn't be
> regarded as log spamming imo. dev_info() honours the 'quiet' kernel
> command line parameter, and so you will only see the message if you
> actually look at the log.
+999
This is exactly as I see it.
If people want a quiet log/fast boot-up times, they can request it.
Otherwise, it's far more useful to trade a second or two for
important information such as which devices are present/enabled on a
platform.
--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
next prev parent reply other threads:[~2019-06-05 8:23 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-04 10:44 [PATCH 1/8] i2c: i2c-qcom-geni: Provide support for ACPI Lee Jones
2019-06-04 10:44 ` [PATCH 2/8] i2c: i2c-qcom-geni: Signify successful driver probe Lee Jones
2019-06-05 6:20 ` Bjorn Andersson
2019-06-05 7:16 ` Lee Jones
2019-06-05 7:22 ` Ard Biesheuvel
2019-06-05 8:23 ` Lee Jones [this message]
2019-06-05 7:56 ` Johan Hovold
2019-06-05 8:20 ` Lee Jones
2019-06-05 8:33 ` Johan Hovold
2019-06-05 8:49 ` Lee Jones
2019-06-05 8:55 ` Johan Hovold
2019-06-05 14:18 ` Wolfram Sang
2019-06-05 18:49 ` Lee Jones
2019-06-12 14:54 ` Johan Hovold
2019-06-04 10:44 ` [PATCH 3/8] pinctrl: msm: Add ability for drivers to supply a reserved GPIO list Lee Jones
2019-06-04 10:44 ` [PATCH 4/8] pinctrl: qcom: sdm845: Provide ACPI support Lee Jones
2019-06-05 6:17 ` Bjorn Andersson
2019-06-05 7:31 ` Lee Jones
2019-06-05 19:06 ` Bjorn Andersson
2019-06-05 19:35 ` Lee Jones
2019-06-04 10:44 ` [PATCH 5/8] soc: qcom: geni: Add support for ACPI Lee Jones
2019-06-04 10:44 ` [PATCH 6/8] usb: dwc3: qcom: Add support for booting with ACPI Lee Jones
2019-06-05 6:35 ` Bjorn Andersson
2019-06-05 7:09 ` Lee Jones
2019-06-05 9:55 ` Lee Jones
2019-06-04 10:44 ` [PATCH 7/8] usb: dwc3: qcom: Start USB in 'host mode' on the SDM845 Lee Jones
2019-06-05 7:00 ` Bjorn Andersson
2019-06-05 8:34 ` Lee Jones
2019-06-05 14:07 ` Jeffrey Hugo
2019-06-05 18:50 ` Lee Jones
2019-06-05 19:14 ` Bjorn Andersson
2019-06-05 19:29 ` Lee Jones
2019-06-04 10:44 ` [PATCH 8/8] usb: dwc3: qcom: Improve error handling Lee Jones
2019-06-05 7:03 ` Bjorn Andersson
2019-06-05 11:42 [PATCH 1/8] i2c: i2c-qcom-geni: Provide support for ACPI Lee Jones
2019-06-05 11:42 ` [PATCH 2/8] i2c: i2c-qcom-geni: Signify successful driver probe Lee Jones
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