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authorBin Meng <bmeng.cn@gmail.com>2016-05-11 14:45:06 (GMT)
committerBin Meng <bmeng.cn@gmail.com>2016-05-23 07:18:00 (GMT)
commit5a6a2c714e74ba18ebd6f890f5f60dc7f0bb0a72 (patch)
tree8246789b26caaf70589cf5af70649c988746ddf7 /doc
parent10fcabed8857d2c12a5806c68cf884802f975aae (diff)
downloadu-boot-5a6a2c714e74ba18ebd6f890f5f60dc7f0bb0a72.tar.xz
x86: doc: Update information about IGD with SeaBIOS
Document how to make SeaBIOS load and run the VGA ROM of Intel IGD device when loaded by U-Boot. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'doc')
-rw-r--r--doc/README.x8624
1 files changed, 24 insertions, 0 deletions
diff --git a/doc/README.x86 b/doc/README.x86
index 25cb218..250d5a3 100644
--- a/doc/README.x86
+++ b/doc/README.x86
@@ -807,6 +807,30 @@ to install/boot a Windows XP OS (below for example command to install Windows).
This is also tested on Intel Crown Bay board with a PCIe graphics card, booting
SeaBIOS then chain-loading a GRUB on a USB drive, then Linux kernel finally.
+If you are using Intel Integrated Graphics Device (IGD) as the primary display
+device on your board, SeaBIOS needs to be patched manually to get its VGA ROM
+loaded and run by SeaBIOS. SeaBIOS locates VGA ROM via the PCI expansion ROM
+register, but IGD device does not have its VGA ROM mapped by this register.
+Its VGA ROM is packaged as part of u-boot.rom at a configurable flash address
+which is unknown to SeaBIOS. An example patch is needed for SeaBIOS below:
+
+diff --git a/src/optionroms.c b/src/optionroms.c
+index 65f7fe0..c7b6f5e 100644
+--- a/src/optionroms.c
++++ b/src/optionroms.c
+@@ -324,6 +324,8 @@ init_pcirom(struct pci_device *pci, int isvga, u64 *sources)
+ rom = deploy_romfile(file);
+ else if (RunPCIroms > 1 || (RunPCIroms == 1 && isvga))
+ rom = map_pcirom(pci);
++ if (pci->bdf == pci_to_bdf(0, 2, 0))
++ rom = (struct rom_header *)0xfff90000;
+ if (! rom)
+ // No ROM present.
+ return;
+
+Note: the patch above expects IGD device is at PCI b.d.f 0.2.0 and its VGA ROM
+is at 0xfff90000 which corresponds to CONFIG_VGA_BIOS_ADDR on Minnowboard MAX.
+Change these two accordingly if this is not the case on your board.
Development Flow
----------------