[coreboot] SeaBIOS and the Geode LX framebuffer

[Marc Jones]

Stephen Crocker wrote:
> Marc Jones wrote:
>> I don't understand that it defaulted to 5530. In sysmgr\sysmgr.h 
>> SUPPORT_CS5536 is the targeted chipset. It has been a long time, but 
>> SUPPORT_CS5535 should also work. I don't know if SUPPORT_CS5530 would 
>> work.
> 
> If you look at the link that I posted, you will see why.  Here is the 
> section of sysmgr.asm in question:
> 
> Start:
> ; NOTE: The VSA II installer patches a "JMP SysMgr_Entry" over the 
> signature field
>     dd    VSM_SIGNATURE        ; VSM signature
>     db    VSM_SYS_MGR        ; VSM type
>     db    0FFh            ; Any CPU
> if SUPPORT_CS5535
>     dw    DEVICE_ID_5535        ; VSA for CS5535
> else
>     dw    DEVICE_ID_5530        ; VSA for CS5530
> endif   
>     dw    VSA_VERSION        ; System Manager version
>     dd    OFFSET edata        ; Size of System Manager
>     dw    OFFSET SysMgr_Entry    ; EntryPoint
>     dd    OFFSET _end        ; DS Limit
>     dw    0007h            ; Requirements: 4096-byte boundary
>      dw    VSA_VERSION        ; VSA version
> 
> As you can see, if SUPPORT_CS5535 is not defined, it will use 
> DEVICE_ID_5530.  Furthermore, it would appear that there is no way for 
> the field to be DEVICE_ID_5536 without modifying the source code. 
> Admittedly, this is a trivial patch but it strikes me as odd that such 
> an action is required.  That is why I was wondering whether a newer 
> version of the source was available.
> 

Ah, This is an oversite on our part. I don't think that anyone uses that 
field in the signature.

Marc

-- 
Marc Jones
Senior Firmware Engineer
(970) 226-9684 Office
mailto:Marc.Jones at amd.com
http://www.amd.com/embeddedprocessors