[coreboot] CBMEM console deactivated in coreboot and activated SeaBIOS

[Paul Menzel]

Dear coreboot folks,

if the CBMEM console is disabled in coreboot and only enabled in
SeaBIOS, currently SeaBIOS does not write any messages to the CBMEM
console (SeaBIOS commit f24eb2f85 (build: CONFIG_VGA_FIXUP_ASM should
depend on CONFIG_BUILD_VGABIOS)).

$ more src/fw/coreboot.c
    […]
    struct cb_cbmem_ref *cbref = find_cb_subtable(cbh, CB_TAG_CBMEM_CONSOLE);
    if (cbref) {
        cbcon = (void*)(u32)cbref->cbmem_addr;
        debug_banner();
        dprintf(1, "Found coreboot cbmem console @ %llx\n", cbref->cbmem_addr);
    }
    […]

Does the CBMEM specification(?) allow to add the CBMEM console
section(?) – CB_TAG_CBMEM_CONSOLE 0x17 – after coreboot has run? If
yes, I could try to adapt SeaBIOS to do just that in case coreboot does
not set it up.

Thanks,

Paul