linux-kernel - Re: [PATCH] clk: Warn about critical clks that fail to enable

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Date:   Mon, 30 Dec 2019 09:55:17 -0800
From:   Stephen Boyd <sboyd@...nel.org>
To:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
        Jerome Brunet <jbrunet@...libre.com>,
        Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH] clk: Warn about critical clks that fail to enable

Quoting Stephen Boyd (2019-12-26 14:13:54)
> If we don't warn here users of the CLK_IS_CRITICAL flag may not know
> that their clk isn't actually enabled because it silently fails to
> enable. Let's drop a big WARN_ON in that case so developers find these
> problems faster.
> 
> Suggested-by: Jerome Brunet <jbrunet@...libre.com>
> Cc: Guenter Roeck <linux@...ck-us.net>
> Signed-off-by: Stephen Boyd <sboyd@...nel.org>
> ---
> 
> I suspect that this may start warning for other users. Let's see
> and revert in case it doesn't work.
> 
>  drivers/clk/clk.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 772258de2d1f..6a9a66dfdeaa 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -3427,13 +3427,13 @@ static int __clk_core_init(struct clk_core *core)
>                 unsigned long flags;
>  
>                 ret = clk_core_prepare(core);
> -               if (ret)
> +               if (WARN_ON(ret))

We should probably just print the clk name that failed to be critically
enabled with a pr_warn(). The traceback pointing to this location will
be really hard to understand otherwise.

>                         goto out;
>  
>                 flags = clk_enable_lock();
>                 ret = clk_core_enable(core);
>                 clk_enable_unlock(flags);
> -               if (ret) {
> +               if (WARN_ON(ret)) {
>                         clk_core_unprepare(core);
>                         goto out;
>                 }
> 
> base-commit: 12ead77432f2ce32dea797742316d15c5800cb32
> -- 
> Sent by a computer, using git, on the internet
>