Merge pull request #91 from ReturnInfinity/UEFI_EDID

UEFI EDID support

Author: IanSeyler

src/boot/uefi.asm

@@ -11,9 +11,6 @@
 ; dd if=PAYLOAD of=BOOTX64.EFI bs=4096 seek=1 conv=notrunc > /dev/null 2>&1
 ; =============================================================================
 
-; Set the desired screen resolution values below
-Horizontal_Resolution		equ 1024
-Vertical_Resolution		equ 768
 
 BITS 64
 ORG 0x00400000
@@ -158,6 +155,65 @@ nextentry:
 	lodsq							; Load the address of the ACPI table
 	mov [ACPI], rax						; Save the address
 
+	; Find the interface to EFI_EDID_ACTIVE_PROTOCOL_GUID via its GUID
+	mov rcx, EFI_EDID_ACTIVE_PROTOCOL_GUID			; IN EFI_GUID *Protocol
+	mov rdx, 0						; IN VOID *Registration OPTIONAL
+	mov r8, EDID						; OUT VOID **Interface
+	mov rax, [BS]
+	mov rax, [rax + EFI_BOOT_SERVICES_LOCATEPROTOCOL]
+	call rax
+	cmp rax, EFI_SUCCESS
+	je get_EDID						; If it exists, process EDID
+
+	; Find the interface to EFI_EDID_DISCOVERED_PROTOCOL_GUID via its GUID
+	mov rcx, EFI_EDID_DISCOVERED_PROTOCOL_GUID		; IN EFI_GUID *Protocol
+	mov rdx, 0						; IN VOID *Registration OPTIONAL
+	mov r8, EDID						; OUT VOID **Interface
+	mov rax, [BS]
+	mov rax, [rax + EFI_BOOT_SERVICES_LOCATEPROTOCOL]
+	call rax
+	cmp rax, EFI_SUCCESS
+	je get_EDID						; If it exists, process EDID
+	jmp use_GOP						; If not found, or other error, use GOP
+
+	; Gather preferred screen resolution
+get_EDID:
+	; Parse the EDID information
+	; 0  UINT32 - SizeOfEdid
+	; 4  UINT8 - *Edid
+	mov rax, [EDID]
+	mov ebx, [rax]
+	cmp ebx, 128						; Minimum size of 128 bytes
+	jb use_GOP						; Fail out to GOP with default resolution
+	mov rbx, [rax+8]					; Pointer to EDID. Why not +4?
+	mov rax, [rbx]						; Load RAX with EDID header
+	mov rcx, 0x00FFFFFFFFFFFF00				; Required EDID header
+	cmp rax, rcx						; Verify 8-byte header at 0x00 is 0x00FFFFFFFFFFFF00
+	jne use_GOP						; Fail out to GOP with default resolution
+	; Preferred Timing Mode starts at 0x36
+	; 0x38 - Lower 8 bits of Horizontal pixels in bits 7:0
+	; 0x3A - Upper 4 bits of Horizontal pixels in bits 7:4
+	; 0x3B - Lower 8 bits of Vertical pixels in bits 7:0
+	; 0x3D - Upper 4 bits of Vertical pixels in bits 7:4
+	xor eax, eax
+	xor ecx, ecx
+	mov al, [rbx+0x38]
+	mov cl, [rbx+0x3A]
+	and cl, 0xF0						; Keep bits 7:4
+	shl ecx, 4
+	or eax, ecx
+	mov [Horizontal_Resolution], eax
+	xor eax, eax
+	xor ecx, ecx
+	mov al, [rbx+0x3B]
+	mov cl, [rbx+0x3D]
+	and cl, 0xF0						; Keep bits 7:4
+	shl ecx, 4
+	or eax, ecx
+	mov [Vertical_Resolution], eax
+
+	; Set video to desired resolution. By default it is 1024x768 unless EDID was found
+use_GOP:
 	; Find the interface to GRAPHICS_OUTPUT_PROTOCOL via its GUID
 	mov rcx, EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID		; IN EFI_GUID *Protocol
 	mov rdx, 0						; IN VOID *Registration OPTIONAL
@@ -203,10 +259,10 @@ vid_query:
 	mov rsi, [vid_info]
 	lodsd							; UINT32 - Version
 	lodsd							; UINT32 - HorizontalResolution
-	cmp eax, Horizontal_Resolution
+	cmp eax, [Horizontal_Resolution]
 	jne next_video_mode
 	lodsd							; UINT32 - VerticalResolution
-	cmp eax, Vertical_Resolution
+	cmp eax, [Vertical_Resolution]
 	jne next_video_mode
 	lodsd							; EFI_GRAPHICS_PIXEL_FORMAT - PixelFormat (UINT32)
 	bt eax, 0						; Bit 0 is set for 32-bit colour mode
@@ -339,6 +395,8 @@ get_memmap:
 	stosq							; EFI_MEMORY_DESCRIPTOR version
 	mov rax, [ACPI]
 	stosq							; ACPI Table Address
+	mov rax, [EDID]
+	stosq							; EDID Data (Size and Address)
 
 	; Set screen to black before jumping to Pure64
 	mov rdi, [FB]
@@ -436,6 +494,7 @@ CONFIG:			dq 0					; Config Table address
 ACPI:			dq 0					; ACPI table address
 OUTPUT:			dq 0					; Output services
 VIDEO:			dq 0					; Video services
+EDID:			dq 0
 FB:			dq 0					; Frame buffer base address
 FBS:			dq 0					; Frame buffer size
 HR:			dq 0					; Horizontal Resolution
@@ -452,12 +511,24 @@ vid_index:		dq 0
 vid_max:		dq 0
 vid_size:		dq 0
 vid_info:		dq 0
+Horizontal_Resolution:	dd 1024					; Default resolution X - If no EDID found
+Vertical_Resolution:	dd 768					; Default resolution Y - If no EDID found
 
 ACPI_TABLE_GUID:
 dd 0xeb9d2d30
 dw 0x2d88, 0x11d3
 db 0x9a, 0x16, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d
 
+EFI_EDID_ACTIVE_PROTOCOL_GUID:
+dd 0xbd8c1056
+dw 0x9f36, 0x44ec
+db 0x92, 0xa8, 0xa6, 0x33, 0x7f, 0x81, 0x79, 0x86
+
+EFI_EDID_DISCOVERED_PROTOCOL_GUID:
+dd 0x1c0c34f6
+dw 0xd380, 0x41fa
+db 0xa0, 0x49, 0x8a, 0xd0, 0x6c, 0x1a, 0x66, 0xaa
+
 EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID:
 dd 0x9042a9de
 dw 0x23dc, 0x4a38