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Date: Tue, 5 Jul 2016 14:26:03 +0200
From: cinap_lenrek@felloff.net
To: 9front@9front.org
Subject: Re: [9front] core-i3 and vesa mode
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X-Glyph: ➈
X-Bullshit: descriptor just-in-time realtime-java-aware solution 

the bios probably didnt map all the graphics memory,
just enougth for the screen on boot.

the kernel vgaigfx driver already has code to
determine how much memory got mapped in the gtt.

we could make it map all the physical memory there
in case the bios didnt do it for us.

static uintptr
gmsize(Pcidev *pci, void *mmio)
{
	u32int x, i, npg, *gtt;

	npg = stolenmb(pci)<<(20-12);
	if(npg == 0)
		return 0;
	gtt = (u32int*)((uchar*)mmio + pci->mem[0].size/2);
	if((gtt[0]&1) == 0)
		return 0;
	x = (gtt[0]>>12)+1;
	for(i=1; i<npg; i++){
		if((gtt[i]&1) == 0 || (gtt[i]>>12) != x)
			break;
		x++;
	}
	if(0) print("igfx: graphics memory at %p-%p (%ud MB)\n", 
		(uintptr)(x-i)<<12, (uintptr)x<<12, (i>>(20-12)));
	return (uintptr)i<<12;
}

--
cinap