Stefan Reinauer wrote:
- Bari Ari bari@onelabs.com [040503 20:44]:
What will be needed to run video on non-x86? The oem videoBIOS plus an 8086 emulator for when videoBIOS calls are made?
Once the operating system is running no video bios calls are needed. It's all only about initializing the graphics hardware in first place. Today's graphics cards need complex ram setup, mode initialization, etc.
I've gotten various answers from graphics chip vendors over the years on all this.
You need the videoBIOS when you first init the device after reset unless you wish to come up with all your own (possibly several hundred) register values.
You may use the videoBIOS when you wish to change the video mode but you may also do it with your own set of register values on the fly.
XFree86 drivers sometimes rely on the videoBIOS, sometimes not.
Is this how the layers end up for video?
video application
GUI/OS Linux
8086 emulator
videoBIOS
graphics hardware
The x86 emulation would be running as part of LinuxBIOS, or as a user space program. Once video is initialized, Linux can take over the hardware and use it's own drivers (which are not capable to initialize the hardware from power on)
I know this is going beyond Ron's plan. Let's say there is source for an XFree86 driver for a graphics device with all the 3-D and Zoom port support. I haven't looked at the emulator yet. Using the 8086 emulator would this support fb driver only? or would you also be able to support XFree86 drivers compiled for ARM?
-Bari