[Intel-gfx] Can't drive 4K monitor at full resolution over DP

[Bryan O'Sullivan]

I have a new Framework laptop running Fedora 35, stock kernel package
5.14.16-301, BDB version 240.

My CPU/GPU is an 11th gen i7-1165G7, connected via a USB-C-to-DP cable to a
2014-era Dell P2715Q monitor that supports 3840x2160 at 60Hz over DP (my Mac
drives it this way just fine).

With i915 debugging enabled, I can see the 4K modeline being detected and
discarded because CLOCK_HIGH. Here's some debug output in a paste as it's
longish and verbose: https://pastebin.com/reGcmxYF

Line 17 of that paste seems weird, where the value of everything is zero
for some reason?

Here's some output from the monitor-edid tool. If there's any more
information I can supply to track this down, I'm happy to do what I can.

Name: DELL P2715Q
EISA ID: DEL40bd
EDID version: 1.4
EDID extension blocks: 1
Screen size: 59.7 cm x 33.6 cm (26.97 inches, aspect ratio 16/9 = 1.78)
Gamma: 2.2
Digital signal
Max video bandwidth: 540 MHz

        HorizSync 31-140
        VertRefresh 29-75

        # Monitor preferred modeline (60.0 Hz vsync, 133.3 kHz hsync, ratio
16/9, 163 dpi)
        ModeLine "3840x2160" 533.25 3840 3888 3920 4000 2160 2163 2168 2222
-hsync +vsync

        # Monitor supported CEA modeline (60.0 Hz vsync, 67.5 kHz hsync,
ratio 16/9, 81 dpi)
        ModeLine "1920x1080" 148.5 1920 2008 2052 2200 1080 1084 1089 1125
+hsync +vsync
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