Re: Creator3D resolution switching

[Sad Clouds <cryintothebluesky%gmail.com@localhost>]

On Sun, 25 Mar 2018 22:02:05 +0100
Julian Coleman <jdc%coris.org.uk@localhost> wrote:

> Hi,
> 
> > Hi, I'm having some issues with Creator3D graphics card and
> > NetBSD-8. On boot, NetBSD automatically switches resolution, but
> > this results in a blank screen with my monitor.
> 
> The ffb driver reads the EDID data and should switch to a mode that is
> supported by the monitor ...
> 
> > I have Dell 1920x1200 monitor, but it doesn't have a VGA port, so
> > I'm using VGA-to-HDMI converter http://www.avaccess.com/c160.html
> 
> ... so I wonder which mode is chosen here.
> 
> > When in OpenBoot, everything is displayed correctly, but as soon as
> > NetBSD boots, I get a blank screen, i.e. no output to monitor.
> 
> What resolution/timing does OFW choose?
> 
> > Is there a way to stop NetBSD from switching resolution, or is
> > there a NetBSD specific ffb command line tool to manually reset
> > resolution from a startup script?
> 
> You can force the resolution using the `output-device' field, for
> example:
> 
>   setenv output-device screen:r1280x1024x60
> 
> (or set it using `eeprom`).
> 
> It would be interesting to see the output from a kernel compiled with
> FFB_DEBUG.  However, because the monitor doesn't handle the mode we
> choose, commenting out all the calls to DAC_WRITE() would show the
> debugging but not change video mode.  See:
> 
>   https://nxr.netbsd.org/xref/src/sys/arch/sparc64/dev/ffb.c#1596
> 
> Regards,
> 
> Julian

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.

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

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?