From e5ffa4bb62b4532079ea552a804178f3955775f9 Mon Sep 17 00:00:00 2001 From: Bin Meng Date: Thu, 22 Oct 2015 19:13:32 -0700 Subject: 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 Acked-by: Simon Glass --- arch/x86/include/asm/arch-queensbay/tnc.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/arch-queensbay/tnc.h b/arch/x86/include/asm/arch-queensbay/tnc.h index 2365394..8477d92 100644 --- a/arch/x86/include/asm/arch-queensbay/tnc.h +++ b/arch/x86/include/asm/arch-queensbay/tnc.h @@ -7,10 +7,9 @@ #ifndef _X86_ARCH_TNC_H_ #define _X86_ARCH_TNC_H_ -/* IGD Control Register */ -#define IGD_GC 0x50 -#define VGA_DISABLE 0x00020000 -#define GMS_MASK 0x00700000 +/* IGD Function Disable Register */ +#define IGD_FD 0xc4 +#define FUNC_DISABLE 0x00000001 /* Memory BAR Enable */ #define MEM_BAR_EN 0x00000001 -- cgit v1.1