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From: =?UTF-8?B?44GN44GP44Gh44KD44KT44GV44KT?= <kikuchan98@gmail.com>
Date: Fri, 24 May 2024 20:32:29 +0900
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Subject: Re: [PATCH v9 0/3] Add support for Allwinner PWM on D1/T113s/R329 SoCs
To: John Watts <contact@jookia.org>
Cc: privatesub2@gmail.com, aou@eecs.berkeley.edu, bigunclemax@gmail.com, 
	conor+dt@kernel.org, devicetree@vger.kernel.org, fusibrandon13@gmail.com, 
	jernej.skrabec@gmail.com, krzk+dt@kernel.org, 
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	linux-sunxi@lists.linux.dev, mkl@pengutronix.de, p.zabel@pengutronix.de, 
	palmer@dabbelt.com, paul.walmsley@sifive.com, robh@kernel.org, 
	samuel@sholland.org, ukleinek@kernel.org, wens@csie.org
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Hi John,

> Does Linux guarantee a flicker-free experience with setting up PWM
> channels, or that it doesn't affect other channels?
> How do other drivers handle this situation?

I've noticed that drivers/pwm/pwm-fsl-ftm.c and
drivers/pwm/pwm-microchip-core.c use a similar approach for shared
resources between PWM channels.
They simply fail if the settings are not applicable to the hardware,
much like this driver does. However, I have yet to find a driver that
aggressively changes another channel that is already running.

Maybe you're right; Linux might not guarantee anything about this.
I think all we can do is deliver the best experience to users within
such limitations.

Best regards,
kikuchan.