Hello !

I have an AOpen vKM400Am-S motherboard with VIA IGP, the AOpen is call KM400A. I
use Gentoo with Xorg 6.8.99.15. I didn't use the X correct on 1024x768 24bpp,
just smaller resolution, until to the next correction. I read on a Debian
mailinglist. Sorry for my not too good english.

http://cvs.freedesktop.org/xorg/xc/programs/Xserver/hw/xfree86/drivers/via/via_mode.c?rev=1.7&view=markup

THE ORIGINAL:

case VIA_KM400:
	if (pVia->ChipRev < 0x8F)
	    return ViaBandwidthTable[VIA_BW_KM400].Bandwidth[pVia->MemClk];
	else
	    return ViaBandwidthTable[VIA_BW_KM400A].Bandwidth[pVia->MemClk];

FINE FOR ME:

	if (pVia->ChipRev < 0x84)



lspci and xorg.log :


0000:01:00.0 VGA compatible controller: VIA Technologies, Inc. VT8378 [S3
UniChrome] Integrated Video (rev 01) (prog-if 00 [VGA])
        Subsystem: VIA Technologies, Inc. VT8378 [S3 UniChrome] Integrated Video
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B-
        Status: Cap+ 66Mhz+ UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
<TAbort- <MAbort- >SERR- <PERR-
        Latency: 32 (500ns min)
        Interrupt: pin A routed to IRQ 10
        Region 0: Memory at e4000000 (32-bit, prefetchable) [size=64M]
        Region 1: Memory at ea000000 (32-bit, non-prefetchable) [size=16M]
        Capabilities: [60] Power Management version 2
                Flags: PMEClk- DSI+ D1+ D2+ AuxCurrent=0mA
PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [70] AGP version 2.0
                Status: RQ=32 Iso- ArqSz=0 Cal=0 SBA+ ITACoh- GART64- HTrans-
64bit- FW- AGP3- Rate=x1,x2,x4
                Command: RQ=1 ArqSz=0 Cal=0 SBA- AGP- GART64- 64bit- FW- Rate=<none>



(--) VIA(0): Chipset: "KM400/KN400"
(--) VIA(0): mapping MMIO @ 0xea000000 with size 0x9000
(--) VIA(0): mapping BitBlt MMIO @ 0xea200000 with size 0x10000
(II) VIA(0): vgaHWGetIOBase: hwp->IOBase is 0x03d0, hwp->PIOOffset is 0x0000
(--) VIA(0): Chipset Rev.: 132
(WW) VIA(0): Manufacturer plainly copied main PCI ids to Subsystem/Card ids.
(--) VIA(0): Detected Biostar iDEQ 200V/Chaintech 7VIF4.
(==) VIA(0): Using gamma correction (1.0, 1.0, 1.0)
(--) VIA(0): videoram =  16384k