linux-kernel - Re: [PATCH] clk: qcom: dispcc-x1e80100: Drop the reconfiguring of PLL0 on probe

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Date: Thu, 18 Apr 2024 15:08:42 +0300
From: Abel Vesa <abel.vesa@...aro.org>
To: Konrad Dybcio <konrad.dybcio@...aro.org>
Cc: Bjorn Andersson <andersson@...nel.org>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
	Rajendra Nayak <quic_rjendra@...cinc.com>,
	linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clk: qcom: dispcc-x1e80100: Drop the reconfiguring of
 PLL0 on probe

On 24-04-18 13:33:19, Konrad Dybcio wrote:
> On 18.04.2024 12:51 PM, Abel Vesa wrote:
> > Currently, PLL0 is configured by the bootloader is the parent of the
> > mdp_clk_src. Reconfiguring it on probe leaves the PLL0 in "stand-by"
> > state (unlocked), which will trigger RCG child clocks to not update
> > their config,
> 
> Sounds like this is the problem that should be fixed instead.
> 
>  which then breaks eDP on all x1e80100 boards. So rely
> > on the bootloader for now. Drop the config values as well. Also add
> > a comment to explain why the PLL0 is not configured alongside PLL1.
> > 
> > Fixes: ee3f0739035f ("clk: qcom: Add dispcc clock driver for x1e80100")
> > Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> > ---
> 
> This works, because you have (at least) partially configured hardware, but
> we shouldn't assume this to be the case.

OK, I think we should be safe to follow trion's approach instead then.

https://lore.kernel.org/all/20211123162508.153711-1-bjorn.andersson@linaro.org/

> 
> Konrad