Re: [PATCH 2/8] i2c: i2c-qcom-geni: Signify successful driver probe

From: Lee Jones <lee.jones@linaro.org>
To: Johan Hovold <johan@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>,
	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
Date: Wed, 5 Jun 2019 09:49:21 +0100	[thread overview]
Message-ID: <20190605084921.GQ4797@dell> (raw)
In-Reply-To: <20190605083353.GD29637@localhost>

On Wed, 05 Jun 2019, Johan Hovold wrote:

> On Wed, Jun 05, 2019 at 09:20:47AM +0100, Lee Jones wrote:
> > On Wed, 05 Jun 2019, Johan Hovold wrote:
> 
> > > No, we don't add noise like this to the logs just because it may be
> > > useful while debugging. Even one-liners add up.
> > 
> > One line per device is should not cause an issue.
> > 
> > Problems occur when developers try to print all kinds of device
> > specifics to the boot log.  A simple, single line for such an
> > important device/controller has more benefits than drawbacks.
> 
> What about the thousands of probe functions which do not currently spam
> the logs? If you want to see all successful probes reliably, you tell
> driver core to print it.
> 
> > > 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.
> > 
> > This is what I ended up doing.  It was time consuming to parse though
> > a log of that size when you have no paging or keyboard.
> 
> With the right command-line option to enable dynamic debugging you get
> one line per successful probe, just like you wanted. Or are you now
> saying that one-line per device is too much after all? ;)

Which command line option are you pertaining to?

> > > 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.
> > 
> > Not in a non-booting system with no keyboard you can't. ;)
> 
> Fair enough, but the above would still work.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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