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If multiple VGA-compatible legacy graphic cards decode the IO range 3B0-3BB, 3C0-3DF and MEM range A00000-BFFFF. Windows 7 complain a resource conflict, so only one VGA card can works at the same time. There is a discussion in coreboot mail list before, please reference thread: "how to prevent legacy resource conflictwith multipleVGA cards" http://www.coreboot.org/pipermail/coreboot/2010-October/061508.html Linux using VGA Arbiter module(vgaarb) to resolve this resource conflict, Please see the following linux dmesg log, more information can be found in Linux source dir Documentation/vgaarbiter.txt. But it seems that windows don't dealwith this conflict. ~# dmesg | grep -i vgaarb [ 0.774076] vgaarb: device added: PCI:0000:00:01.0,decodes=io+mem,owns=io+mem [ 0.776065] vgaarb: device added: PCI:0000:01:00.0,decodes=io+mem,owns=none,l [ 0.780051] vgaarb: loaded [ 0.784049] vgaarb: bridge control possible 0000:01:00.0 [ 0.788050] vgaarb: bridge control possible 0000:00:01.0 For the second legacy graphic device, coreboot already disabled the IO and MEM decode in function set_vga_bridge_bits(). But it will be enabled again in function pci_set_resource(), if the second legacy vga-compatible graphic device take any IO/MEM resources. Following log printed by enable_resources() shows the problem: ...snip... PCI: 00:00.0 cmd <- 06 PCI: 00:01.0 subsystem <- 1022/1410 PCI: 00:01.0 cmd <- 07 <== The first graphic device PCI: 00:01.1 subsystem <- 1022/1410 PCI: 00:01.1 cmd <- 02 PCI: 00:02.0 bridge ctrl <- 0003 PCI: 00:02.0 cmd <- 07 ...snip... PCI: 01:00.0 cmd <- 03 <== The second graphic device PCI: 01:00.1 cmd <- 02 PCI: 02:00.0 cmd <- 02 PCI: 03:00.0 cmd <- 03 done. ...snip... The IO & MEM decoding on the second vga graphic device should be disabled. Please reference PCI spec. section 3.10 in detail. set_vga_bridge_bits() would do this work for us, it did the right thing, but was put to the wrong place, the setting would be overwritten by assign_resources() later. In order to make sure the set_vga_bridge_bits() setting not be overwritten by others, moving the call of set_vga_bridge_bits() to the end of dev_configure(), instead of at the beginning. This patch resolved the dual graphic cards resource conflict in windows7, multiple vga-compatible graphic cards can work together in windows7. Signed-off-by: Kerry Sheh <shekairui@gmail.com> Signed-off-by: Kerry Sheh <kerry.she@amd.com> Change-Id: I0de5e3761b51e2723d9c1dc0c39fff692e3a779d Reviewed-on: http://review.coreboot.org/489 Tested-by: build bot (Jenkins) Reviewed-by: Marc Jones <marcj303@gmail.com>
------------------------------------------------------------------------------- coreboot README ------------------------------------------------------------------------------- coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload. With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required. coreboot was formerly known as LinuxBIOS. Payloads -------- After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot. See http://www.coreboot.org/Payloads for a list of supported payloads. Supported Hardware ------------------ coreboot supports a wide range of chipsets, devices, and mainboards. For details please consult: * http://www.coreboot.org/Supported_Motherboards * http://www.coreboot.org/Supported_Chipsets_and_Devices Build Requirements ------------------ * gcc / g++ * make Optional: * doxygen (for generating/viewing documentation) * iasl (for targets with ACPI support) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig') * flex and bison (for regenerating parsers) Building coreboot ----------------- Please consult http://www.coreboot.org/Build_HOWTO for details. Testing coreboot Without Modifying Your Hardware ------------------------------------------------ If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU. Please see http://www.coreboot.org/QEMU for details. Website and Mailing List ------------------------ Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website: http://www.coreboot.org You can contact us directly on the coreboot mailing list: http://www.coreboot.org/Mailinglist Copyright and License --------------------- The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details. coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details. This makes the resulting coreboot images licensed under the GPL, version 2.