X trouble on Rpi3, was Re: Missing /dev/io on rpi3 running 12-stable

[bob prohaska]

On Sat, May 23, 2020 at 06:20:13PM -0700, Mark Millard wrote:
> 
> Unfortunately (until there is an MFC of the relevant
> change from head that makes things work), man scfb
> reports that you have no control because the
> information is ignored:
> 
>        For this driver it is not required to specify modes in the Screen
>        section of the configuration file.  The scfb driver picks up the
>        currently used video mode from the framebuffer driver and uses it.
>        Video modes specifications in the configuration file are ignored.
> 
> The fix that is in FreeBSD's head is in
> sys/arm/broadcom/bcm2835/bcm2835_fbd.c :
> 
> QUOTE
> Revision 352028 - (view) (download) (annotate) - [select for diffs] 
> Modified Sun Sep 8 09:47:21 2019 UTC (8 months, 2 weeks ago) by gonzo 
> File length: 7261 byte(s) 
> Diff to previous 331229
> [rpi] Inherit framebuffer BPP value from the VideoCore firmware
> 
> Instead of using hardcoded bpp of 24, obtain current/configured value
> from VideoCore. This solves certain problems with Xorg/Qt apps that
> require bpp of 32 to work properly. The mode can be forced by setting
> framebuffer_depth value in config.txt
> 
> PR:		235363
> Submitted by:	Steve Peurifoy <ssw01 at mathistry.net>
> END QUOTE
> 
> Any version prior to being based on that sort of change needs
> code changes for scfb to work. (It is too late for any
> already-made final-releases to work.)
> 
> The reason that it used to work was a bug/defect in the
> RPi* firmware that did not actually use 24 bits for the
> frame buffer bits per pixel when it was specified: it
> implicitly used 32 instead.
> 
> The one place that 24 does work for the RPi*'s is for the
> console display. That is why they have not simply
> disallowed 24 frame buffer bits per pixel in general.
> 

It looks as if the required bug report already exists:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=246319

Would any further noisemaking be constructive? Squeaky wheels
and all that 8-) 

Thanks for reading and taking the time to explain what's happened!

bob prohaska