linux-kernel - Re: [PATCH 1/3] media: qcom: camss: vfe: Stop spamming logs with version

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Message-ID: <aBIYHD3o3wTfvg_g@hovoldconsulting.com>
Date: Wed, 30 Apr 2025 14:31:24 +0200
From: Johan Hovold <johan@...nel.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
	Robert Foss <rfoss@...nel.org>, Todor Tomov <todor.too@...il.com>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	linux-media@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] media: qcom: camss: vfe: Stop spamming logs with
 version

On Wed, Apr 30, 2025 at 10:19:13AM +0200, Krzysztof Kozlowski wrote:
> On 30/04/2025 09:25, Johan Hovold wrote:
> > On Tue, Apr 29, 2025 at 08:08:29PM +0200, Krzysztof Kozlowski wrote:
> >> Camss drivers spam kernel dmesg with 64 useless messages during boot:
> >>
> >>   qcom-camss acb7000.isp: VFE:1 HW Version = 3.0.2
> >>   qcom-camss acb7000.isp: VFE:2 HW Version = 2.4.0
> >>
> >> All of these messages are the same, so it makes no sense to print same
> >> information 32 times.
> > 
> > It's even worse then that (several hundred messages during use) and I
> > sent fixes for these regressions a few weeks ago:
> > 
> > 	https://lore.kernel.org/lkml/20250407104828.3833-1-johan+linaro@kernel.org/
> > 	https://lore.kernel.org/lkml/20250407085125.21325-1-johan+linaro@kernel.org/
> 
> Oh damn...
> 
> I developed this on top of next, so already with your fixes included,
> but - following standard kernel coding practice that drivers should be
> silent on success - I think even debug messages are not needed here.

Ah, ok, it's based on my fixes and just removing the debug printks.

I think that should be made more clear in the commit message as debug
printks are not enabled by default and the rules for those are less
strict.

> There is really no point in printing (even as debug) version of hw block
> EVERY TIME I boot the hardware. It does not change, does it?

Well, it doesn't hurt to print it once on probe if this is something
read out from the hardware, but clearly printing it hundreds of times
during use make that debug statement pretty useless.

Johan