linux-kernel - Re: [PATCH 1/7] media: cedrus: Disable engine after each slice decoding

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Message-ID: <20190603113827.2nmm5wkycf44aqox@flea>
Date:   Mon, 3 Jun 2019 13:38:27 +0200
From:   Maxime Ripard <maxime.ripard@...tlin.com>
To:     Jernej Skrabec <jernej.skrabec@...l.net>
Cc:     paul.kocialkowski@...tlin.com, wens@...e.org, mchehab@...nel.org,
        gregkh@...uxfoundation.org, linux-media@...r.kernel.org,
        devel@...verdev.osuosl.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/7] media: cedrus: Disable engine after each slice
 decoding

Hi,

On Thu, May 30, 2019 at 11:15:10PM +0200, Jernej Skrabec wrote:
> libvdpau-sunxi always disables engine after each decoded slice.
> Do same in Cedrus driver.
>
> Presumably this also lowers power consumption which is always nice.
>
> Signed-off-by: Jernej Skrabec <jernej.skrabec@...l.net>

Is it fixing anything though?

I indeed saw that cedar did disable it everytime, but I couldn't find
a reason why.

Also, the power management improvement would need to be measured, it
can even create the opposite situation where the device will draw more
current from being woken up than if it had just remained disabled.

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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