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| author | David Woodhouse <David.Woodhouse@intel.com> | 2013-02-08 15:52:01 +0000 |
|---|---|---|
| committer | Kevin O'Connor <kevin@koconnor.net> | 2013-02-08 21:28:45 -0500 |
| commit | c0a2284d858d463ec11597815d542d11fceac768 (patch) | |
| tree | 6844f1dbac703f82b929699ac097d9e069b7e5da | |
| parent | b1885fc3a7998fe91f488a5e54705e606223dc4c (diff) | |
| download | seabios-c0a2284d858d463ec11597815d542d11fceac768.tar.gz | |
Add README.CSM
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
| -rw-r--r-- | README.CSM | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/README.CSM b/README.CSM new file mode 100644 index 0000000..ea71846 --- /dev/null +++ b/README.CSM @@ -0,0 +1,21 @@ +Enabling CONFIG_CSM allows SeaBIOS to be built as a Compatibility Support +Module for use with the OMVF/EDK-II UEFI firmware. + +It will provide "legacy" BIOS services for booting non-EFI operating +systems and will also allow OVMF to display on otherwise unsupported +video hardware by using the traditional VGA BIOS. + +Windows 2008r2 is known to use INT 10h BIOS calls even when booted via +EFI, and the presence of a CSM makes this work as expected too. + +Having built SeaBIOS with CONFIG_CSM, you should be able to drop the +result into your OVMF build tree at OvmfPkg/Csm/Csm16/Csm16.bin and +then build OVMF with 'build -D CSM_ENABLE'. The SeaBIOS binary will be +included as a discrete file within the 'Flash Volume' which is +created, and there are tools which will extract it and allow it to be +replaced; satisfying the requirements of the LGPL licence. + +A patch to OVMF is required, to prevent it from marking the region from +0xC0000-0xFFFFF as read-only before invoking our Legacy16Boot method. See +http://www.sourceforge.net/mailarchive/forum.php?thread_name=50FD7290.9060003%40redhat.com&forum_name=edk2-devel + |