Re: [PATCH] clk: sunxi-ng: ccu-sun4i-a10: Fix mali changing dclk frequency

[Maxime Ripard]

On Wed, Jan 31, 2018 at 01:05:38PM +0100, Giulio Benetti wrote:
> 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.

I guess this patch could fix it:
http://code.bulix.org/1kitrq-268936?raw

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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