The Linux/m68k Frame Buffer Device
 : Converting XFree86 timing values into frame buffer device timings
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  7. Converting XFree86 timing values into frame buffer device timings
An XFree86 mode line consists of the following fields:
    "800x600"     50      800  856  976 1040    600  637  643  666
    < name >     DCF       HR  SH1  SH2  HFL     VR  SV1  SV2  VFL
    
The frame buffer device uses the following fields:
- pixclock
- pixel clock in ps (pico seconds) 
- left_margin
- time from sync to picture 
- right_margin
- time from picture to sync 
- upper_margin
- time from sync to picture 
- lower_margin
- time from picture to sync 
- hsync_len
- length of horizontal sync 
- vsync_len
- length of vertical sync 
- Pixelclock
- 
 - 
- xfree: in MHz
- fb: In Picoseconds (ps)
- pixclock = 1000000 / DCF
 
- Horizontal timings
- 
 - 
- left_margin = HFL - SH2
- right_margin = SH1 - HR
- hsync_len = SH2 - SH1
 
- Vertical timings
- 
 - 
- upper_margin = VFL - SV2
- lower_margin = SV1 - VR
- vsync_len = SV2 - SV1
 
Good examples for VESA timings can be found in the XFree86 source tree,
under xc/programs/Xserver/hw/xfree86/doc/modeDB.txt.
 
The Linux/m68k Frame Buffer Device
 : Converting XFree86 timing values into frame buffer device timings
Previous: Video Mode Timings
Next: References