[Bug 107476] DisplayPort and LSPCON always defaults to incorrect limited-range RGB on Intel Graphics for 24bpp+ displays

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=107476

--- Comment #13 from Tom Yan <tom.ty89 at gmail.com> ---
But I am unsure why the function call
"drm_default_rgb_quant_range(adjusted_mode)" seems to always return the value
corresponding to "HDMI_QUANTIZATION_RANGE_LIMITED" on every DisplayPort
connector of each monitor I try.

I told you the reason already. It's because it determines the range to be used
base on the "mode" of the monitor. Here mode means resolution / refresh rate
combinations.

This whole mess didn't started by Intel, but VESA, because they wanted to
*replace/succeed* HDMI (completely, not in the alt mode sense). As HDMI was
proprosed by the big bosses in AV world (who produces bluray player, AV Amps
and such), they have to make limited range as their first class citizen because
of historical/technical reasons.

The stupidity started when VESA thought DP could really become domination of
both the AV world and the computer/general-purpose world by ignoring the
technical and finanical reality. They simply copy the part of HDMI that try to
compatible with the computer world as much as possible instead of actually
having the spec make sense to the world it should have targeted. That's why I
called DP some cheap braindead copycat work.

Then the monitor vendors started to produce monitors that has a CEA mode as
optimal mode because of the popularity of "Full HD", while at the same time
they didn't care much about color range (vendors are always lazy and ignorant
about spec conformance, and to be fair limited range simply doesn't make sense
in devices that are supposed to be general-purpose instead "av-specific").

Then Linux-part Intel decided that they should be spec-conforming no matter how
ridiculous the spec is. Then it put the attribute/magic in kernel. Then it
decided that the only interface to override it should be in X instead of in
kernel. Tada, here comes the shit.

And end of story, coz no one would give a damn and they just continue to earn
their salary for nothing (or worse), or move on to ruin the world even further
in other company/organization for a even higher pay.

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