Re: Creator3D resolution switching

[Julian Coleman <jdc%coris.org.uk@localhost>]

Hi,

> Hello, yes I can use "setenv output-device ..." to set various
> resolutions, the problem happens when NetBSD boots and resets that
> resolution to something else, and screen goes blank. It would be nice
> to have some command line tool to control ffb, similar to Solaris
> fbconfig. Maybe I'll look into writing one.

This looks like a bug that has been there for ages.  If you look at line 263:

  https://nxr.netbsd.org/xref/src/sys/arch/sparc64/dev/ffb.c#263

we check "output_device", but it should check "output-device"!  Can you
check with "_" changed to "-"?

> > I'll follow your suggestion, enable FFB_DEBUG and comment out
> > DAC_WRITE calls.

Thanks - it would be useful to see all the parameters of the video mode.

> > It also makes me wonder, Creator3D can support max resolution of
> > 1600x1200, but my monitor is 1920x1200, is it possible that
> > sparc64/dev/ffb.c tries to force graphics card into 1920x1200 which it
> > can't support and it just gives up?
> 
> I had a look at the spec and looks like this model of Creator3D can
> handle up to 1920x1200. Also looking at dmesg I can see NetBSD setting
> resolution to 1920x1080, which should be supported:

Creator3D should handle 1920x1360, but I've never tried a vertical resolution
greater than 1200.  I used a Blade 2000 with two Creator3D's at 1920x1200
(connected to Samsung SM245B monitors) for a long time, so I know that it
works.

> ffb0 at mainbus0 addr 0xfebee000: Creator3D, model SUNW,501-4788, dac 10
> ffb0: video mode set to 1920 x 1080 @ 60Hz
> ffb0: attached to /dev/fb0
> 
> Maybe the VGA converter is buggy. 

FFB only handles some combinations of sync signals, so we're probably setting
something that the monitor can't handle, rather than the converter.

We allow writing to the FFB registers from userland, so that it's possible to
alter the resolution, timing, etc.  I do have a prototype `ffbcfg` which I've
uploaded to:

  http://ftp.netbsd.org/pub/NetBSD/misc/jdc/sparc64/ffbcfg.tar.gz

If you alter the resolution, neither wscons nor X are aware of that, so I
would recommend using it only if you have a serial console, remote access, or
if the FFB is not the console framebuffer.

Regards,

Julian