SunSolve Internal

Infodoc ID		Synopsis		Date
2221		Setting the resolution of secondary frame buffer		12 Apr 2000

Description

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A machine can have more than one frame buffer installed, sometimes known
as being "multi-headed."


The resolution of the PRIMARY frame buffer can be set in the NVRAM.
For example: to change the resolution to 1280x1024x76, user would use
the command:

	# eeprom output-device=screen:r1280x1024x76
	
or from the system monitor prompt:

	ok setenv output-device screen:r1280x1024x76
	ok reset

To change the secondary frame buffer it is a little more complex. 

The following script assumes sun4m architecture.  For sun4c/sun4u 
architecture change /iommu/sbus to /sbus

It also assumes that the frame buffer is in sbus slot #3
	- to change this to (say) 2, change cgsix@3 to cgsix@2

Finally it assumes a resolution of r1280x1024x76
	- substitute whatever value is appropriate.

#############################################################################

#!/bin/sh

eeprom fcode-debug\?=true
eeprom nvramrc='probe-sbus
" /iommu/sbus/cgsix@3" select-dev
r1280x1024x76
" /iommu/sbus/cgsix@3" " set-resolution" execute-device-method drop

device-end
install-console
banner
'
eeprom use-nvramrc\?=true

##############################################################################

Here is the procedure to use:

1. Boot the system up 
2. Determine which sbus slot the frame buffer board resides in for the second
   head.
   Do this with the command
   	# dmesg | grep cgsix
  	cgsix1 at sbus0: SBus slot 3 0x0 pri 7
	                     ^^^^^^^^
3. Determine the system architecture. Do this with the command
	# uname -m
	sun4m
4. Modify the script accordingly. Make sure that it is executable.  
   	# chmod 755 scriptname

5. Execute the script, there should be no error messages.
   If an error message such as "not found" is displayed, check to make sure
   that the closed single quotes in the above script are being used properly.

6. Once the script has been executed error free, reboot the system.

7. To determine whether or not the 2nd head has been reconfigured to the 
   proper resolution, use the command:

	# dmesg | grep cgsix
	cgsix0 at SBus slot 1 0x0 pri 7
	cgsix0: screen 1280x1024, double buffered, 4M mappable, rev 11
	cgsix1 at SBus slot 3 0x0 pri 7
	cgsix1: screen 1280x1024, double buffered, 4M mappable, rev 11

The script will only need to be run once, since the configuration will be 
stored in the NVRAM.