Note: This is Sun internal information only!  Please be careful what you
send to customers!

The pgx card can support 24 bit color to an extent. The following table is 
extracted from http://chroma.eng.sun.com/gss-web/pgx/#resolutions

Maximum Screen Resolution 
 
This table gives the maximum possible resolution available with the PGX 
as a function of available memory.  Currently, UltraSPARC(R) 5 & 10 systems 
are available only with 2 meg. 
                             Depth 
       Memory   8-bit       16-bit      24-bit      32-bit
       2M       1600x1280   1152x900    800x600     800x600
       4M       1920x1200   1600x1280   1152x900    1152x900
       8M       1920x1200   1920x1200   1600x1280   1600x1280
 
16-bit graphics are not available at this time. 
32-bit depth provides 24-bit truecolor visuals 

Which resolutions your particular pgx supports depends on the model you have.
For an on-board framebuffer, the model of pgx can be deduced from the 
motherboard part number. The command 'prtconf -pv | grep 375' when run on an 
ultra 5 or 10 will return (as of February 1999) either 375-0009 or 375-0066.

The 375-0009 motherboard is the original ultra 5/10. The pgx on this mother-
board is officially an 8 bit framebuffer. The table above makes it clear
that this framebuffer will support 24 bit color at 800x600 or lower resolution.
This is not a supported configuration.

The 375-0066 motherboard, sometimes called the PGX24[TM], is the "new" ultra 5/10
motherboard. This variant of the pgx is officially a 24 bit framebuffer. The
output of 'dmesg | grep m64' shows that this framebuffer has 4M of memory, so
the highest resolution supported at 24bit color is 1152x900.

PGX32[TM] (Mango) is based on 3Dlabs Permedia2 chip along with 8MB SGRAM.  
It will provide high resolution in the 24-bit windowing environment.  
The resolution for 8-bit and 24-bit windowing in simultaneous mode 
will support resolution up to 1280 x 1024 and 8-bit windowing resolution 
up to 1600 x 1200. Note that this differs from the table above.

To use the pgx in 24 bit mode, use the m64config command to change to a 
resolution that supports the desired color depth, then either use the m64config
command with the -depth option or modify Xservers appropriately. Note that if 
there is a setting in Xservers, it will override the m64config setting.

Example: set a pgx24 to use 24 bit at 1152x900 using m64config

# m64config -res 1152x900x76 now
# m64config -depth 24

# m64config -prconf

--- Hardware Configuration for /dev/fbs/m640 ---
ASIC: version 0x7c004750
DAC: version 0x0
PROM: version 104
Card possible resolutions:  720x400x88, 640x480x60, 640x480x72, 640x480x75
        800x600x56, 800x600x60, 800x600x72, 800x600x75, 1024x768x87
        1024x768x60, 1024x768x70, 1024x768x75, 1280x1024x75, 1280x1024x60
        1152x900x66, 1152x900x76, 1280x1024x67, 1280x800x76, 1280x1024x85
        1280x1024x76, 1152x864x75, 1024x768x77, 1024x800x84, vga, svga
        1152, 1280, 800x600, 1024x768, 1280x1024, 1152x900
Monitor possible resolutions:  720x400x70, 720x400x88, 640x480x60
        640x480x67, 640x480x72, 640x480x75, 800x600x56, 800x600x60
        800x600x72, 800x600x75, 832x624x75, 1024x768x60, 1024x768x70
        1024x768x75, 1280x1024x75, 1152x870x75, 1152x900x66, 1152x900x76
        1280x1024x67, 1280x1024x76, vga, svga, 1152, 1280, 800x600
        1024x768, 1280x1024, 1152x900
Possible depths:  8, 24
Current resolution setting: 1152x900x76
Current depth: 24

Then start OpenWin/CDE and use xdpyinfo to confirm the setting.

Example: set a pgx24 to use 24 bit color depth using Xservers
The relevant line in Xservers should look like:

   :0   Local local_uid@console root /usr/openwin/bin/X -dev /dev/fb defdepth 24