Re: Creator3D resolution switching

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

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