linux-kernel - Re: [PATCH] clk: Don't try to enable critical clocks if prepare failed

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Message-Id: <20191226215919.CFD572080D@mail.kernel.org>
Date:   Thu, 26 Dec 2019 13:59:19 -0800
From:   Stephen Boyd <sboyd@...nel.org>
To:     Guenter Roeck <linux@...ck-us.net>,
        Jerome Brunet <jbrunet@...libre.com>,
        Michael Turquette <mturquette@...libre.com>
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clk: Don't try to enable critical clocks if prepare failed

Quoting Guenter Roeck (2019-12-26 09:22:10)
> On 12/26/19 1:51 AM, Jerome Brunet wrote:
> > 
> > However, we would not want a critical clock to silently fail to
> > enable. This might lead to unexpected behavior which are generally hard
> > (and annoying) to debug.
> > 
> > Would you mind adding some kind of warning trace in case this fails ?
> > 
> 
> The really relevant information is:
> 
> bcm2835-clk 3f101000.cprman: plld: couldn't lock PLL
> 
> which is already displayed (and not surprising since cprman isn't implemented
> in qemu). While I agree that an error message might be useful, replacing
> one traceback with another doesn't really make sense to me, and I am not
> really a friend of spreading tracebacks throughout the kernel. Please feel
> free to consider this patch to be a bug report, and feel free to ignore it
> and suggest something else.

Can the cprman device node be disabled or removed in the DT that qemu
uses? If it isn't actually implemented then it shouldn't be in the DT.
Presumably that will make this traceback go away.