Messages in this thread | | | From | Vincent ETIENNE <> | Subject | AMD64-AGP pb with AGP APERTURE on IWILL DK8N | Date | Tue, 28 Dec 2004 20:49:48 +0000 |
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Hello ALL,
I have some problem with AGP initialization with my board : IWLL DK8N (Bi opteron chipset NFORCE3 ). I use kernel 2.6.10-rc3-mm1, but i have try with different kernel always with the same result :
IOMMU reports a 128MB aperture for CPU0 ( that's the value i used in my bios) at F0000000 but only 32MB at 4000000 for CPU1 and declare i have no valid aperture as show in this dmesg extract.
Checking aperture... CPU 0: aperture @ f0000000 size 128 MB CPU 1: aperture @ 4000000 size 32 MB Aperture from northbridge cpu 1 too small (32 MB) AGP bridge at 00:00:00 Aperture from AGP @ f0000000 size 4096 MB (APSIZE 0) Aperture from AGP bridge too small (0 MB) Your BIOS doesn't leave a aperture memory hole
So i have forced the value at CPU1 to be the same as CPU0 in arch/x86_64/kernel/aperture.c function iommu_hole_init with the following code. Don't asked me what i have done i have quite no idea of what is involved by this modification.
I have add 2 var for memorizing value of aperture_size and base of the first cpu and set the value of the second one to the value of the first one on case they are diferent ( added line marked with a "+" sign ).
void __init iommu_hole_init(void) { int fix, num; u32 aper_size, aper_alloc = 0, aper_order; u64 aper_base; + u32 last_aper_order = 0; + u64 last_aper_base = 0; int valid_agp = 0;
if (iommu_aperture_disabled || !fix_aperture) return; printk("Checking aperture...\n"); fix = 0; for (num = 24; num < 32; num++) { char name[30]; if (read_pci_config(0, num, 3, 0x00) != NB_ID_3) continue;
iommu_aperture = 1; aper_order = (read_pci_config(0, num, 3, 0x90) >> 1) & 7; aper_size = (32 * 1024 * 1024) << aper_order; aper_base = read_pci_config(0, num, 3, 0x94) & 0x7fff; aper_base <<= 25; printk("CPU %d: aperture @ %Lx size %u MB\n", num-24, aper_base, aper_size>>20); + if ( last_aper_order ) + { + if ( aper_order != last_aper_order ) + { + printk("Aperture size changed!! use old one (%x,%x)", last_aper_order, last_aper_base ); + write_pci_config(0, num, 3, 0x90, last_aper_order<<1); + write_pci_config(0, num, 3, 0x94, last_aper_base>>25); + aper_order = last_aper_order; + aper_base = last_aper_base; + aper_size = (32 * 1024 * 1024) << aper_order; + } + } + last_aper_order = aper_order; + last_aper_base = aper_base;
Rest of the code unchanged.
Now agp is enabled 8x, SBA and fast write activated (as seeen in /proc/driver/nvidia/agp/status ) and i'm very pleased but also frustated as i have no idea of that i have done.
Do you think it's more a bios problem (something not initialized correctly by the bios as it seem ) or could it be a kernel bug ? Someone could explain what value sould be returned ? Is my modification secured (at least for my board ) i.e. is this modification could harm some hardware ?
I wish to be personally CC'ed the answers/comment as i'm not a subscriber of a list.
Thanks for your time.
Vincent ETIENNE - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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