linux-kernel - Re: [PATCH v2 06/15] clk: qcom: gpucc-sm6115: Unregister critical clocks

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Date:   Wed, 29 Nov 2023 23:09:24 +0100
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>
Cc:     Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v2 06/15] clk: qcom: gpucc-sm6115: Unregister critical
 clocks

On 29.11.2023 22:14, Bryan O'Donoghue wrote:
> On 29/11/2023 18:59, Konrad Dybcio wrote:
>> Some clocks need to be always-on, but we don't really do anything
>> with them, other than calling enable() once and telling Linux they're
>> enabled.
>>
>> Unregister them to save a couple of bytes and, perhaps more
>> importantly, allow for runtime suspend of the clock controller device,
>> as CLK_IS_CRITICAL prevents the latter.
>>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>> ---
[...]


> 
> OTOH.
> 
> Seems a pity to remove these clocks - generally for the series I mean - from the debug view in /sys/kernel/debug/clk_summary.
> 
> In the ideal case we have pm runtime functional without dropping these clocks from the view in /sys/kernel/debug/clk_summary.
> 
> Certainly I've found that interface useful when launching a real product. It might be confusing to _not_ see the always-on clocks enumerated there.
> 
> ---
I have shared the very same concern in the past.. I did also however realize
that debugfs is not accurate, especially with funky clocks that need only be
enabled once (*even if you gate the e.g. MM subsystem*) and debugcc should be
used instead

Konrad