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

[Saarinen, Jani]

Hi Bryan. 
Can you file new bug: https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs 

Br,

Jani Saarinen
Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo



> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Bryan
> O'Sullivan
> Sent: sunnuntai 14. marraskuuta 2021 6.36
> To: intel-gfx at lists.freedesktop.org
> Subject: [Intel-gfx] Can't drive 4K monitor at full resolution over DP
> 
> 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