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

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Message-ID: <6c78d1343b92e08c92e568a9e349fe22ac2f4aed.camel@collabora.com>
Date:   Mon, 12 Aug 2019 10:28:11 -0300
From:   Ezequiel Garcia <ezequiel@...labora.com>
To:     Maxime Ripard <maxime.ripard@...tlin.com>,
        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 Jernej,

On Mon, 2019-06-03 at 13:38 +0200, Maxime Ripard wrote:
> 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.
> 

While reviewing this, I'm noticing that cedrus_engine_disable can
be marked for static storage (with or without this patch).

Regards,
Eze