Method and apparatus for identifying hardware compatibility and enabling stable software images

A computer system comprising:

• a processor;
• memory coupled to the processor;
• a graphics controller coupled to the processor;
• a storage device to store instructions comprising an initialization software;
• a revision ID register readable by the processor;
• a stepping revision ID register to maintain a value indicating the actual stepping revision level of a first hardware component;
• at least one compatible revision ID register to maintain a value indicating a stepping revision level of a second hardware component that may be used with a same piece of software as the first hardware component;
• and
• selection logic to enable the selection of a value from either the stepping revision ID register or one of the at least one compatible revision ID registers, the selected value to be readable by the processor.

A computer system comprising:

• a first processor;
• a second processor;
• a graphics controller coupled to the first and second processors;
• a storage device to store instructions comprising an initialization software;
• a revision ID register readable by the first processor;
• a stepping revision ID register to maintain a value indicating the actual stepping revision level of a first hardware component;
• at least one compatible revision ID register to maintain a value indicating a stepping revision level of a second hardware component that may be used with a same piece of software as the first hardware component;
• and
• selection logic accessible by the second processor to enable the selection of a value from either the stepping revision ID register or one of the at least one compatible revision ID registers and to make the value readable from the revision ID register by the first processor.

A method comprising:

• using a security key to gain access to a selection logic;
• using the selection logic to select a value from either a stepping revision ID register maintaining a value indicating the actual stepping revision level of a first hardware component or one of the at least one compatible revision ID registers maintaining a value indicating a stepping revision level of a second hardware component that may be used with a same piece of software as the first hardware component;
• and
• making the selected value readable by a processor when the processor reads the selected value through a revision ID register.

A machine-accessible medium comprised of instructions that, if executed by a processor of a machine, will cause the machine to:

• use a security key to gain access to a selection logic;
• use the selection logic to select a value from either a stepping revision ID register maintaining a value indicating the actual stepping revision level of a first hardware component or one of the at least one compatible revision ID registers maintaining a value indicating a stepping revision level of a second hardware component that may be used with a same piece of software as the first hardware component;
• and
• make the selected value readable by the processor when the processor later reads the selected value through a revision ID register.