Re: SUNW,m46B resolutions?

[Michael <macallan%netbsd.org@localhost>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hello,

On Jun 13, 2011, at 11:42 PM, der Mouse wrote:

> > > I have a U5 whose framebuffer is a SUNW,m64B [...] machfb0 [...]
>
> > The machfb driver is a full fledged kernel driver and should be able
> > to change the device's resolution to anything you want once the OS is
> > loaded.
>
> How?  I'm not familiar with any interface that allows changing a
> framebuffer's resolution after booting.  I even had a quick look at  
> the
> driver and didn't see anything.  What should I go read up on?

There is no userland interface. If the driver finds an EDID block in  
its device properties it will try to use the monitor's preferred mode.  
The mode needs to be listed in sys/dev/videomode/modelines too.

> > Of course your monitor needs to support this resolution.
>
> In my case I care for pretty much the converse reason: I want the
> machine to support the preferred resolution of the monitor.  (It's a
> flatscreen....)

IIRC the PGX supports DDC but it doesn't work through all 13W3-VGA  
adaptors ( my PGX has a 13w3 and I have two adaptors - one that does  
connect the right pins and one that doesn't )
Both work well enough to get something displayed on the monitor but  
DDC works through only one.
Also, the firmware may not know how to setup the monitor's preferred  
mode - often they only have parameter sets for a handful modes  
considered standard at the time the firmware was written.
Unfortunately it's not really possible to support DDC directly in  
machfb - ATI only added it as an afterthought and abused some generic  
GPIOs to do it, which ones exactly varies with chip revision, board  
manufacturer, moon phase etc. and can't really be probed either.

> > You can `see' show-modes and mode# to see what they are and if they
> > take a parameter to dump the entire table.
>
> I've looked there.  There's a constant which appears to be a bitmask  
> of
> supported modes.  That value is 4 - corresponding to mode 2, the one  
> it
> printed. :-(  I don't know whether this is because I haven't connected
> it to a monitor since last power-on so it didn't get any EDID data or
> because it's just an unusually impoverished variant I have or what.

That looks very much like a bunch of Apple graphics cards I've seen. I  
bet the card supports DDC in some way.

have fun
Michael

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (Darwin)

iQEVAwUBTfb5xspnzkX8Yg2nAQI3swf/fwnD4Q5wQLYBJwMNaHWJk4tgJhgzoBsd
mI9enSOdLZenDFvcgTGOrC5JXMBLszVh5orCPND5BleNSCBgoaUwu/2OnjgzjHCP
MDrTOYIKpYErYcq/RngL4+fJfJOnM6xo9k+hD3l5KINuTGDcyR4Auj+MxOrPt+dw
Koxe5qyHLDvYKlm1YzTZp3HSem390CQOs1x/j+2QuoQ/eI6FUBaPZOjuxhRuV3SB
59PhQyNIkVi8Bzse/Kfyk9X4P7YmH21Wb42KFn1+zmi9TQ2mJKM6N3gFMNFU9z1A
KxN/RwFd8qOStXTTuO2oS8AX9aNd3TIvfVeUngzqF+rl/RPVX//r2A==
=y7Ur
-----END PGP SIGNATURE-----