Re: graphical console: limit resolution?

[mlelstv%serpens.de@localhost (Michael van Elst)]

wiz%NetBSD.org@localhost (Thomas Klausner) writes:

>The card's limit is 2560x1440 (I think), but the graphical console
>code doesn't care and tries to switch to 3840x2160 and the screen is
>just black afterwards.

>Is there a way to limit the resolution for the graphical console
>(e.g., a kernel config parameter)?

I don't think so.

drm_helper_probe_single_connector_modes_merge_bits() filters the
modes reported by the monitor.

- drm_mode_validate_basic()
checks for sane timings

- drm_mode_validate_size()
checks against max dimension. You could add arbitrary additional limits here.

- drm_mode_validate_flag()
checks for special modes (interlace, double scan, 3D).

- driver specific mode_valid()
checks for card and port limits, e.g. pixel clock or sync timings. This
probably may need to be fixed to handle your card correctly.


drm_fb_helper_single_fb_probe() later selects the largest width and largest
height (not necessarily from the same mode, which seems to be bogus).


-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."