port-sparc64/59408: machfb picks a really odd console resolution

[nia%pkgsrc.org@localhost]

>Number:         59408
>Category:       port-sparc64
>Synopsis:       machfb picks a really odd console resolution
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-sparc64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu May 08 21:00:00 +0000 2025
>Originator:     nia
>Release:        10.1
>Organization:
The MachBSFB Foundation
>Environment:
NetBSD lilac 10.1_STABLE NetBSD 10.1_STABLE (GENERIC) #0: Thu May  8 19:43:59 CEST 2025  nia@siphon:/encrypt/src/obj/sys/arch/sparc64/compile/GENERIC sparc64
>Description:
machfb sees a 1080p screen and decides it's far too large:

[     1.000000] machfb0: unable to use EDID preferred mode (1920 x 1080)
[     1.000000] machfb0: initializing the DSP
[     1.000000] machfb0: initial resolution 1280x800 at 8 bpp

then picks 1280x800, despite the aspect ratio being wrong!

The monitor does display this, but a lot of the display is
cut off.

The video chip is capable of handling the native resolution of
the monitor - I know because it uses it when X is started.
>How-To-Repeat:
boot netbsd with framebuffer
>Fix:
machfb.c contains the following line:

#define MODE_IS_VALID(m) ((sc->ramdac_freq >= (m)->dot_clock) && \
                          ((m)->hdisplay <= 1280))

This line can be adjusted, but I'm unsure of the rationale for
it existing. Saving memory?