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Subject: Re: [PATCH] drm/sun4i: init dclk_min_div & dclk_max_div inside
 encoder init functions
From:   Giulio Benetti <giulio.benetti@micronovasrl.com>
To:     Maxime Ripard <maxime.ripard@bootlin.com>
Cc:     David Airlie <airlied@linux.ie>, Chen-Yu Tsai <wens@csie.org>,
        dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <1519822318-3974-1-git-send-email-giulio.benetti@micronovasrl.com>
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Message-ID: <83d1a6d8-0816-9f75-34f6-4b93e84393e4@micronovasrl.com>
Date:   Wed, 28 Feb 2018 19:22:14 +0100
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Hi,

Il 28/02/2018 17:34, Giulio Benetti ha scritto:
> Hi,
> 
> Il 28/02/2018 16:55, Maxime Ripard ha scritto:
>> Hi,
>>
>> On Wed, Feb 28, 2018 at 01:51:58PM +0100, Giulio Benetti wrote:
>>> sun4i_dclk_round_rate is called before sun4i_tcon_mode_set,
>>> so it finds dclk_min_div and dclk_max_div set to 0 and fails
>>> adding crtc.
>>>
>>> Move dclk_min_div and dclk_max_div to encoders init functions.
>>>
>>> Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com>
>>
>> I sent a similar patch there:
>> https://lists.freedesktop.org/archives/dri-devel/2018-February/166666.html 
>>
> 
> I've missed that.
> And where you put it is better, since it's called every time set_mode is 
> called.
> 
> On lvds instead I don't see anything about this,
> it should have the same potential problem.
> Also I can't understand why it has been set min=7 and max=7 on lvds.
> With those values I would obtain 77Mhz only.
> And I can't find values on datasheet for minimum and maximum.

Submitted patchset for that.

> 
>>
>> I guess eventually, we'll want to remove the usage of the clock
>> framework entirely, but it's not really the scope of a fix.
> 
> Where would you handle dclk instead of tcon?

Don't mind.

-- 
Giulio Benetti
CTO

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> 
> Thanks
>