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Subject: Re: [PATCH v4 09/17] drm/uAPI: Add "active color range" drm property
 as feedback for userspace
To:     Pekka Paalanen <ppaalanen@gmail.com>,
        Simon Ser <contact@emersion.fr>
Cc:     amd-gfx@lists.freedesktop.org, sunpeng.li@amd.com,
        intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org, airlied@linux.ie,
        tzimmermann@suse.de, rodrigo.vivi@intel.com,
        alexander.deucher@amd.com, christian.koenig@amd.com
References: <20210618091116.14428-1-wse@tuxedocomputers.com>
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 <20210623103256.01d680ba@eldfell>
From:   Werner Sembach <wse@tuxedocomputers.com>
Message-ID: <5947f768-dd87-6b39-ecfc-b7c4aaa88aca@tuxedocomputers.com>
Date:   Wed, 23 Jun 2021 12:17:40 +0200
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Am 23.06.21 um 09:32 schrieb Pekka Paalanen:
> On Tue, 22 Jun 2021 11:48:52 +0000
> Simon Ser <contact@emersion.fr> wrote:
>
>> On Tuesday, June 22nd, 2021 at 11:50, Werner Sembach <wse@tuxedocomputers.com> wrote:
>>
>>> Unknown is when no monitor is connected or is when the
>>> connector/monitor is disabled.  
>> I think the other connector props (link-status, non-desktop, etc) don't
>> have a special "unset" value, and instead the value is set to a random
>> enum entry. User-space should ignore the prop on these disconnected
>> connectors anyways.
> That sounds fine to me.

Currently the only case for "not applicable" is when the monitor is disconnected, but sicne the properties are so
interdependent, there might be a case in the future where e.g. a color format that has no differentiation between full
and limited arises. When there is no special unset/not applicable option, the userspace has to know exactly when an
option is valid or not, possible requiring additional logic.

Setting a "not applicable" value allows userspace to be more dumb, without much hassle on the kernelspace side.

>
>
> Thanks,
> pq
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