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Evan Hillas (evanh)
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My first HTML  :)  created just to document the options added to the vesa driver.

First step, cut'n'paste from the original post at www.qnxzone.com


VESA Driver Tweaked for Speed

The QNX 6.x Photon VESA driver is known for it's sluggish performance and fixed 60 Hz refresh rate.  This experimental version has two improvements, a virtual frame buffer and settable refresh rate.

Download, then place the file in your "/lib/dll" directory.  Be sure it is marked executable.

The virtual frame buffer (shadow buffer) is the same method that the SVGA (vbe 1.x) driver uses.  This has proven to be a faster solution for desktop use on Photon, it improves scrolling and dragging while degrading ordinary draw speed.  A switch for turning it off has been added.

The settable refresh rate is a big relief for those sitting in front of a 60 Hz CRT display all day long.  This still needs improving as the prefs don't know about it so you have to manually edit the command in "Advanced" and add, for example, -R85 for a 85 Hz display.

There is a restriction on the use of the refresh rate control - your graphics card must support VBE 3.0 or greater.

Email: evanh@clear.net.nz


Second step, throw in some comments and document the new options.

nsb=noshadowbuffer - Disable the virtual frame buffer.   Either of the two option names can be used to perform the option.


The following options are for those souls that have a graphics mode that just isn't quite right.  Again, this feature requires a VBE 3.0 compliant card.    It allows adjustment of the mode timings relative to the default calculated settings.  All values are signed integers, so can be negative.

vt=vtotal  -  Adjust the total number of lines for a complete video frame.  Unit is lines.
ht=htotal  -  Adjust the total number of dots for a complete scanline.  Unit is dots(pixels).
vss=vsyncstart  -  Shift the vertical sync pulse.  Unit is lines.
hss=hsyncstart  -  Shift the horizontal sync pulse.  Unit is dots.
vsl=vsynclen  -  Adjust size of the vertical sync pulse.  Unit is lines.
hsl=hsynclen  -  Adjust size of the horizontal sync pulse.  Unit is dots.
dc=dotclock  -  Adjust the dot clock (pixel clock) rate.  Unit is kilohertz.
rf=refresh  -  Adjust the video frame rate.  Unit is hertz.  Most cards ignore this setting prefering dotclock instead.

Say you wanted to shift the picture down the display a little bit, this is a simple matter of subtracting a few lines from the vertical sync start, eg:  vsyncstart=-5  or  vss=-5

Next is a complete example for an imaginary graphics card.  This adjusts three of the options in the vesa driver. 


io-graphics -R75 -amode=vt=10:vss=-3:vsl=-1 -dldevg-vesabios.so -g1024x768x16 -I0 -d0x1234,0x4321

You can see I've set a refresh rate of 75 hertz and a graphics mode of 1024x768, from that a standard set of timing values are created and applied to get you a display.  But there is the addition of the -amode=.... that adjusts three of the timing values.