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<b><a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - 12bpc hdmi causes wrong real refresh rate (swapbuffers return time)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=93361#c14">Comment # 14</a>
on <a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - 12bpc hdmi causes wrong real refresh rate (swapbuffers return time)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=93361">bug 93361</a>
from <span class="vcard"><a class="email" href="mailto:tomeu@tomeuvizoso.net" title="Tomeu Vizoso <tomeu@tomeuvizoso.net>"> <span class="fn">Tomeu Vizoso</span></a>
</span></b>
<pre>(In reply to Kevin Mitchell from <a href="show_bug.cgi?id=93361#c0">comment #0</a>)
<span class="quote">> Created <span class=""><a href="attachment.cgi?id=120472" name="attach_120472" title="Samsung un40eh5000 edid reported by xrandr --prop">attachment 120472</a> <a href="attachment.cgi?id=120472&action=edit" title="Samsung un40eh5000 edid reported by xrandr --prop">[details]</a></span>
> Samsung un40eh5000 edid reported by xrandr --prop
>
> I have a Samsung un40eh5000 tv that I connect to my Ivy Bridge Lenovo T530
> laptop via mini display-port to hdmi. I have attached the raw and decoded
> EDID.
>
> As of 7a0baa6234468aa387f9b8a1a79dc2a4b4821f67, it seems 12bpc gets enabled
> on this setup (though I can't imagine that my machine or my TV actually
> support that in real life).</span >
Why do you think that? The EDID says that DC_36bit is supported, and from sandy
bridge up, 12bpc is supported by the graphics hw.
<span class="quote">> Unfortunately, this seems to change the
> effective refresh rate as measured between returns from opengl swapbuffers
> calls for example in glxgears.
>
> | glxgears fps |
> +----------------+
> xrandr | before | after |
> -------+--------+-------+
> 23.98 | 24.00 | 23.85 |
> 24.00 | 24.00 | 24.13 |
> 29.97 | 30.00 | 29.81 |
> 30.00 | 30.00 | 30.17 |
> 59.94 | 60.00 | 60.12 |
> 60.00 | 60.00 | 60.12 |
>
> This is problematic for displaying video at native frame rates. For example
> when the actual refresh rate of 24.00 hz could be achieved, 23.98fps video
> would only have to repeat a frame every 50 seconds. Now it must either drop
> or repeat one every 7 seconds which is much more noticeable.</span >
So you want a mechanism for disabling deep color even if it could be used?</pre>
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