u-boot-brain/arch/x86/cpu/queensbay
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
..
fsp_configs.c x86: Move common FSP code into a common location 2015-02-05 22:16:43 -07:00
Kconfig x86: Allow disabling IGD on Intel Queensbay 2015-10-21 07:46:25 -06:00
Makefile x86: Convert to use driver model pci on queensbay/crownbay 2015-07-28 10:36:24 -06:00
tnc.c x86: queensbay: Really disable IGD 2015-11-13 06:46:20 -08:00
topcliff.c x86: mmc: Move common FSP functions into a common file 2015-02-06 12:07:36 -07:00