[coreboot] Fwd: SimNOW VGA int 1a
Rudolf Marek
r.marek at assembler.cz
Sat Oct 18 23:48:52 CEST 2008
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>> Basically, vga bios tries to size a 16 meg register and at an
>> intermediate point the vga hardware ends up decoding the top 16 mb of
>> memory.
Hi all,
I think one _must_ disable the decoders first by disabling space in PCI_COMMAND
register. Check u-boot how it does:
http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=blob;f=drivers/pci/pci_auto.c;hb=HEAD
It first disable the cmdstat = (cmdstat & ~(PCI_COMMAND_IO |
PCI_COMMAND_MEMORY)) | PCI_COMMAND_MASTER;
And then goes to decode. VIA bridge has also _default_ enable decode, so it
blows up very badly when probing without decode enabled. Check K8M890
k8t890_bridge.c
Rudolf
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