u-boot-brain/arch/x86
Bin Meng e5ffa4bb62 x86: queensbay: Really disable IGD
According to Atom E6xx datasheet, setting VGA Disable (bit17)
of Graphics Controller register (offset 0x50) prevents IGD
(D2:F0) from reporting itself as a VGA display controller
class in the PCI configuration space, and should also prevent
it from responding to VGA legacy memory range and I/O addresses.

However test result shows that with just VGA Disable bit set and
a PCIe graphics card connected to one of the PCIe controllers on
the E6xx, accessing the VGA legacy space still causes system hang.
After a number of attempts, it turns out besides VGA Disable bit,
the SDVO (D3:F0) device should be disabled to make it work.

To simplify, use the Function Disable register (offset 0xc4)
to disable both IGD (D2:F0) and SDVO (D3:F0) devices. Now these
two devices will be completely disabled (invisible in the PCI
configuration space) unless a system reset is performed.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-11-13 06:46:20 -08:00
..
cpu x86: queensbay: Really disable IGD 2015-11-13 06:46:20 -08:00
dts Various Makefiles: Add SPDX-License-Identifier tags 2015-11-10 09:19:52 -05:00
include/asm x86: queensbay: Really disable IGD 2015-11-13 06:46:20 -08:00
lib x86: Rename pcat_ to i8254 and i8259 accordingly 2015-11-13 06:46:18 -08:00
config.mk efi: Add 64-bit payload support 2015-08-05 08:44:07 -06:00
Kconfig x86: Move CONFIG_8259_PIC and CONFIG_8254_TIMER to Kconfig 2015-11-13 06:46:19 -08:00
Makefile x86: Add support for U-Boot as an EFI application 2015-08-05 08:44:06 -06:00