Arch Linux

kokoko3k

Member

Registered: 2008-11-14

Posts: 2,426

15Khz crt monitor, kms and radeon 9250

It is not really an issue, yet.

I use an old gentoo system with 2.6.16 kernel with an arcade monitor which syncs signal at about 15Khz/60Hz, not more.
I use it as an emulator box which runs advancemame through svgalib (so i need my framebuffer to be 2D accelerated) and other 3D emulators through Xorg (so i need Xorg to be 3d accelerated).
Video card is an old AGP radeon 9250 with a modified firmware which output to 15Khz right from bios.
I modified a modeline in /src/linux/drivers/video/modedb.c to be 15Khz and i call that mode right from grub by passing video=radeonfb:<mymodename>; Xorg modeline is also 15Khz/60Hz.
That way, my linux box can always be seen on the arcade monitor.

Now I'd like to upgrade the system to Arch Linux, but as far as i understood, i will have problems because of kms, which is not compatible with radeonfb.
So here's my concerns:

- Are svgalib and kms compatible each other (read: will 2d framebuffer acceleration through svgalib still be available with kms)?

- Does xf86-video-ati needs kms in order to enable 3d Hardware acceleration in X?
---- And if not, does the 3d performance decreases if i disable kms?

- I really doubt kms will be able to identify my CRT monitor through edid, because i don't think it will provide any, so is there a way to use kms and pass a custom mode as kernel parameter?
---- And if not, If  disable kms at boot time (by booting in plain text mode, which still will be 15Khz), can i load it afterwards and set a custom video mode through fbset?

Thanks for reading

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