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

From: Giulio Benetti
Date: Fri Feb 02 2018 - 12:31:00 EST


Hi,

Il 02/02/2018 16:52, Maxime Ripard ha scritto:
On Fri, Feb 02, 2018 at 04:38:13PM +0100, Giulio Benetti wrote:
Hi,

Il 02/02/2018 14:35, Maxime Ripard ha scritto:
On Fri, Feb 02, 2018 at 11:57:20AM +0100, Giulio Benetti wrote:
Il 02/02/2018 11:53, Maxime Ripard ha scritto:
Hi,

On Thu, Feb 01, 2018 at 05:17:11PM +0100, Giulio Benetti wrote:
What kernel version did you use?

Latest mainline.

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

This should prevent from modifying parent clock. But my problem was
different.

On A20, gpu_clk can have different PLL, not I've found out the way
to choose right one with assigned-parent-clocks.

I have patchset ready for adding A20 mali node, but I need some more
time to complete with OPP, then I will submit entire patchset.

Now it works correctly, using right pll(dedicated PLL8), setting
right frequency.

The point is that we really don't care about which PLL is actually
being used, as long as the rate is correct and we don't break anything
else. If the GPU rate is accessible through one of the other PLL, it
makes even more sense to not use the GPU PLL and keep it disabled,
since it will result in some power savings.

Ah! I see the point now, very clever system for power saving.
I'm going to check if it's resolutive,
but it sounds good.


Btw, do I need to add a board using it, or can I add only Mali node
to sun7i-a20.dtsi(plus other little patches)?

You can add it to the DTSI without a board using it (and actually,
nothing should be in the board DTS, everything in the DT for the Mali
applies to all boards).

Sure. So I would also add the patch you've addressed me:
http://code.bulix.org/1kitrq-268936?raw
as a commit. Can I submit it in patchset to complete the whole job?

I already sent that patch quite some time ago, I'll just apply it. You
can send the DT patch :)

Thanks. Sorry for my ignorance, but where are you applying patches?
Because I've tried to check sunxi-next and a lot of other Repo but I can't
find this and neither "Re: [PATCH] clk: sunxi-ng: ccu-sun4i-a10: Fix mali
changing dclk frequency"

Usually, in the git tree listed in MAINTAINERS :)

Please don't laugh at me! :)

I've tried to check for your patch(drivers/gpu/drm/sun4i/sun4i_tcon.c) on:
https://cgit.freedesktop.org/drm/drm-misc/
according to MAINTAINERS file and nothing found.

For the other one(arch/arm/boot/dts/sun7i-a20.dtsi), I've checked
on:
https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux.git/
https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git/
https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/

Nothing neither here!

In MAINTANERS file there's no arch/arm/boot/dts/sun* association.

I don't know where else to look, I'm going nut!
And for sure I'm looking idiot,
this is why I've prepended "Please don't laugh at me!" :))

Help!


Maxime



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Advanced Research

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