Re: [coreboot] [Bug?] 3 different bytes in VGAbios after upgrade to coreboot

[Rudolf Marek]

Hi all,


Dne 7.6.2015 v 02:12 Vladimir napsal(a):
> Thank you very much for solving this riddle!
> And one more question for Rudolf: please tell, are you using atomDis
> utility to disassemble atombios into C code? Or there are some other
> special tools, which probably have more recent versions? (latest version of
> atomDis is already 4 years old...)

I think there was some effort to make VGA BIOS from scratch. I think the guys
used a script to rewrite it to C. I don't remember anymore.

Thats all I know,

Thanks
Rudolf
> On 3 June 2015 at 20:27, Rudolf Marek <[e-mail]> wrote:
> > Hi all,
> >
> > First byte after IBM is usually a checksum. So in fact only two bytes
> > differ.
> > Now you may ask what it is... and it is a IOBASE :)
> >
> > typedef struct _ATOM_ROM_HEADER
> > {
> >   ATOM_COMMON_TABLE_HEADER sHeader;
> >   UCHAR> uaFirmWareSignature[4];    /*Signature to distinguish between
> > Atombios
> > and non-atombios,atombios should init it as "ATOM", don't change the
> > position */
> >   USHORT usBiosRuntimeSegmentAddress;
> >   USHORT usProtectedModeInfoOffset;
> >   USHORT usConfigFilenameOffset;
> >   USHORT usCRC_BlockOffset;
> >   USHORT usBIOS_BootupMessageOffset;
> >   USHORT usInt10Offset;
> >   USHORT usPciBusDevInitCode;
> >   USHORT usIoBaseAddress; <---------------this changes
> >
> > I guess IOBASE of PCI device changes also...
> >
> > USHORT usSubsystemVendorID;
> >   USHORT usSubsystemID;
> >   USHORT usPCI_InfoOffset;.
> >   USHORT usMasterCommandTableOffset; /*Offset for SW to get all command
> > table
> > offsets, Don't change the position */
> >   USHORT usMasterDataTableOffset;   /*Offset for SW to get all data table
> > offsets, Don't change the position */
> >   UCHAR  ucExtendedFunctionCode;
> >   UCHAR  ucReserved;
> > }ATOM_ROM_HEADER;
> >
> > You can use atomDis to dump it I guess (Did not check if it dumps also the
> > header.
> >
> > Thanks
> > Rudolf