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Subject: Re: [PATCH] clk: sunxi-ng: ccu-sun4i-a10: Fix mali changing dclk
 frequency
To:     Maxime Ripard <maxime.ripard@free-electrons.com>
Cc:     Chen-Yu Tsai <wens@csie.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@codeaurora.org>,
        linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1517354639-92978-1-git-send-email-giulio.benetti@micronovasrl.com>
 <20180131084349.du2ijvhh5rxa5vvt@flea.lan>
From:   Giulio Benetti <giulio.benetti@micronovasrl.com>
Message-ID: <7be1e297-4fac-a7a2-a8cc-54061d4e2fde@micronovasrl.com>
Date:   Wed, 31 Jan 2018 13:05:38 +0100
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Hi,

Il 31/01/2018 09:43, Maxime Ripard ha scritto:
> Hi,
> 
> On Wed, Jan 31, 2018 at 12:23:59AM +0100, Giulio Benetti wrote:
>> When mali.ko is inserted, it set default clocks and call all parent
>> clocks to stay into range, causing pll-video0 to change and
>> subsequently to change dclk to wrong frequencies.
> 
> This is what you should fix.

Ok, so it must be patch title(shrinked of course), right?

> 
>> "gpu" clock has lot of parent plls inside driver, but on sun7i
>> pll8-gpu does not depend on pll-video0, pll-ve, pll-video1.
>>
>> It only depends on 24Mhz main clock.
> 
> I don't really know why you are mentionning that. The GPU clock has
> all the parents described in the driver. And the parents' parents are
> irrelevant to this particular issue.
> 
>> Remove all pll parents from gpu_parents_sun7i except "pll-gpu".
> 
> However, this is not a proper fix for your issue.

Yes, you're right, now I understand.

It is more complex than I thought.
I need to dig more and study better A20 CCU.

So this patch can be dropped.

> 
> What kernel version did you use?

Latest mainline.

> 
> Maxime
> 


-- 
Giulio Benetti
R&D Manager &
Advanced Research

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