Merge branch 'master' into core32

Conflicts:
	core/extlinux.asm
	core/isolinux.asm
	core/ldlinux.asm
	core/pxeidle.inc
	core/pxelinux.asm

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

15 files changed, 123 insertions, 150 deletions

diff --git a/NEWS b/NEWS
index 5e9be215..c7fddff5 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,11 @@ Changes in 3.81:
 	* Shuffler: fix bug in real-mode entry.  This affected a
 	  number of modules, probably in relatively unimportant ways,
 	  but it completely broke linux.c32.
+	* Improved performance.
+	* Attempt to halt the processor while idle.  This can cause
+	  bad reponsiveness when using a serial console especially for
+	  automated input; if that ends up being a problem, use the
+	  new "NOHALT 1" configuration command.
 
 Changes in 3.80:
 	* New shuffler mechanism and API.
diff --git a/core/comboot.inc b/core/comboot.inc
index b1048bb5..57e631ef 100644
--- a/core/comboot.inc
+++ b/core/comboot.inc
@@ -391,24 +391,11 @@ comboot_getchar:
 ;
 ; INT 28h - DOS idle
 ;
-%ifdef HAVE_IDLE
 comboot_int28:
 		cli
 		cld
-		pushad
-		xor ax,ax
-		push ds
-		push es
-		mov ds,ax
-		mov es,ax
-		DO_IDLE
-		pop es
-		pop ds
-		popad
+		call do_idle
 		iret
-%else
-comboot_int28	equ comboot_iret
-%endif
 
 ;
 ; INT 29h - DOS fast write character
@@ -724,22 +711,11 @@ comapi_dnsresolv equ comapi_err
 ;
 ; INT 22h AX=0013h	Idle call
 ;
-;
-; *** FIX THIS ***
-; The idle call seems to have detrimental effects on some machines when
-; called from a COM32 context (WHY?) --  disable it for now.
-; *** IS THIS STILL TRUE? ***
-;
-%ifdef HAVE_IDLE
 comapi_idle:
-		DO_IDLE
+		call do_idle
 		clc
 		ret
 
-%else
-comapi_idle	equ comapi_err
-%endif
-
 ;
 ; INT 22h AX=0014h	Local boot
 ;
@@ -1067,7 +1043,7 @@ zero_string	db 0			; Empty, null-terminated string
 ; in pxe_detect_nic_type
 ;
 feature_flags:
-		db 3			; Have local boot, idle is noop
+		db 1			; Have local boot, idle is not noop
 feature_flags_len equ ($-feature_flags)
 
 err_notdos	db ': attempted DOS system call INT ',0
diff --git a/core/common.inc b/core/common.inc
index 09491e51..ad64c23c 100644
--- a/core/common.inc
+++ b/core/common.inc
@@ -16,4 +16,5 @@
 %include "graphics.inc"		; VGA graphics
 %include "highmem.inc"		; High memory sizing
 %include "strcpy.inc"           ; strcpy()
+%include "idle.inc"		; Idle handling
 %include "adv.inc"		; Auxillary Data Vector
diff --git a/core/conio.inc b/core/conio.inc
index 3e606619..08cf5382 100644
--- a/core/conio.inc
+++ b/core/conio.inc
@@ -286,7 +286,7 @@ write_serial_str:
 ;
 pollchar:
 		pushad
-		DO_IDLE
+		call do_idle
 		mov ah,11h		; Poll keyboard
 		int 16h
 		jnz .done		; Keyboard response
@@ -312,7 +312,7 @@ pollchar:
 ;
 getchar:
 .again:
-		DO_IDLE
+		call do_idle
 		mov ah,11h		; Poll keyboard
 		int 16h
 		jnz .kbd		; Keyboard input?
@@ -330,8 +330,10 @@ getchar:
 		cmp al,ah
 		jne .again
 .serial:	xor ah,ah		; Avoid confusion
-		xchg dx,bx		; Data port
+		mov dx,bx		; Data port
 		in al,dx
+		lea dx,[bx+2]		; DX -> IIR
+		in al,dx		; Read IIR to discard any IRQ bits
 		ret
 .kbd:		mov ah,10h		; Get keyboard input
 		int 16h
@@ -344,7 +346,7 @@ getchar:
 		mov bx,KbdMap		; Convert character sets
 		xlatb
 .func_key:
-		RESET_IDLE		; Character received
+		call reset_idle		; Character received
 		ret
 
 %ifdef DEBUG_TRACERS
@@ -392,6 +394,7 @@ FlowControl	equ $
 FlowOutput	resb 1			; Outputs to assert for serial flow
 FlowInput	resb 1			; Input bits for serial flow
 FlowIgnore	resb 1			; Ignore input unless these bits set
+FlowDummy	resb 1			; Unused
 
 TextAttribute   resb 1			; Text attribute for message file
 DisplayMask	resb 1			; Display modes mask
diff --git a/core/extlinux.asm b/core/extlinux.asm
index 9f8ef8f8..3a054b22 100644
--- a/core/extlinux.asm
+++ b/core/extlinux.asm
@@ -47,16 +47,6 @@ ROOT_DIR_WORD	equ 0x002F
 CUR_DIR_DWORD	equ 0x00002F2E
 
 ;
-; This is what we need to do when idle
-;
-%macro	RESET_IDLE 0
-	; Nothing
-%endmacro
-%macro	DO_IDLE 0
-	; Nothing
-%endmacro
-
-;
 ; The following structure is used for "virtual kernels"; i.e. LILO-style
 ; option labels.  The options we permit here are `kernel' and `append
 ; Since there is no room in the bottom 64K for all of these, we
diff --git a/core/idle.inc b/core/idle.inc
new file mode 100644
index 00000000..4b073641
--- /dev/null
+++ b/core/idle.inc
@@ -0,0 +1,50 @@
+;; -*- fundamental -*- ---------------------------------------------------
+;;
+;;   Copyright 2008 H. Peter Anvin - All Rights Reserved
+;;   Copyright 2009 Intel Corporation; author: H. Peter Anvin
+;;
+;;   This program is free software; you can redistribute it and/or modify
+;;   it under the terms of the GNU General Public License as published by
+;;   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+;;   Boston MA 02110-1301, USA; either version 2 of the License, or
+;;   (at your option) any later version; incorporated herein by reference.
+;;
+;; -----------------------------------------------------------------------
+
+		section .text16
+TICKS_TO_IDLE	equ 4
+
+reset_idle:
+		push ax
+		mov ax,[cs:BIOS_timer]
+		mov [cs:IdleTimer],ax
+		pop ax
+		ret
+
+do_idle:
+		push ax
+		push ds
+		push es
+		mov ax,cs
+		mov ds,ax
+		mov es,ax
+		mov ax,[BIOS_timer]
+		sub ax,[IdleTimer]
+		cmp ax,TICKS_TO_IDLE
+		jb .done
+		call [IdleHook]
+		cmp word [NoHalt],0
+		jne .done
+		hlt
+.done:
+		pop es
+		pop ds
+		pop ax
+.ret:		ret
+
+		section .data16
+NoHalt		dw 0
+IdleHook	dw do_idle.ret
+
+		section .bss16
+IdleTimer	resw 1
diff --git a/core/isolinux.asm b/core/isolinux.asm
index 3be435b7..4ed12a74 100644
--- a/core/isolinux.asm
+++ b/core/isolinux.asm
@@ -40,16 +40,6 @@ SECTOR_SIZE	equ (1 << SECTOR_SHIFT)
 ROOT_DIR_WORD	equ 0x002F
 
 ;
-; This is what we need to do when idle
-;
-%macro	RESET_IDLE 0
-	; Nothing
-%endmacro
-%macro	DO_IDLE 0
-	; Nothing
-%endmacro
-
-;
 ; The following structure is used for "virtual kernels"; i.e. LILO-style
 ; option labels.  The options we permit here are `kernel' and `append
 ; Since there is no room in the bottom 64K for all of these, we
diff --git a/core/keywords b/core/keywords
index aeafb96d..c289ae29 100644
--- a/core/keywords
+++ b/core/keywords
@@ -32,6 +32,7 @@ ontimeout
 onerror
 noescape
 nocomplete
+nohalt
 f0
 f1
 f2
diff --git a/core/keywords.inc b/core/keywords.inc
index 4923441f..d0f7db36 100644
--- a/core/keywords.inc
+++ b/core/keywords.inc
@@ -77,6 +77,7 @@ keywd_table:
 		keyword allowoptions,	pc_setint16,	AllowOptions
 		keyword noescape,	pc_setint16,	NoEscape
 		keyword nocomplete,	pc_setint16,	NoComplete
+		keyword nohalt,		pc_setint16,	NoHalt
 		keyword f1,		pc_filename,	FKeyN(1)
 		keyword f2,		pc_filename,	FKeyN(2)
 		keyword f3,		pc_filename,	FKeyN(3)
diff --git a/core/ldlinux.asm b/core/ldlinux.asm
index 9e90916c..c08799f4 100644
--- a/core/ldlinux.asm
+++ b/core/ldlinux.asm
@@ -51,16 +51,6 @@ DIRENT_SIZE	equ (1 << DIRENT_SHIFT)
 ROOT_DIR_WORD	equ 0x002F
 
 ;
-; This is what we need to do when idle
-;
-%macro	RESET_IDLE 0
-	; Nothing
-%endmacro
-%macro	DO_IDLE 0
-	; Nothing
-%endmacro
-
-;
 ; The following structure is used for "virtual kernels"; i.e. LILO-style
 ; option labels.  The options we permit here are `kernel' and `append
 ; Since there is no room in the bottom 64K for all of these, we
diff --git a/core/parseconfig.inc b/core/parseconfig.inc
index 77afaa65..e6819bf7 100644
--- a/core/parseconfig.inc
+++ b/core/parseconfig.inc
@@ -178,9 +178,8 @@ pc_include:	inc word [IncludeLevel]
 pc_serial:	call getint
 		jc .err
 		push bx				; Serial port #
-		xor ax,ax
-		mov [FlowControl],ax		; Default to no flow control
-		mov [FlowIgnore],al
+		xor eax,eax
+		mov [FlowControl],eax		; Default to no flow control
 		call skipspace
 		jc .nobaud
 		call ungetc
@@ -200,7 +199,7 @@ pc_serial:	call getint
 		shl bh,4
 		mov [FlowIgnore],bh
 		mov bh,bl
-		and bx,0F003h			; Valid bits
+		and bx,0F00Bh			; Valid bits
 		mov [FlowControl],bx
 		pop ebx				; Baud rate
 		jmp short .parse_baud
@@ -247,7 +246,8 @@ pc_serial:	call getint
 		jne .err			; Assume serial port busted
 		dec dx
 		dec dx				; DX -> IER
-		xor al,al			; IRQ disable
+		test byte [FlowOutput],8
+		setnz al			; Bit 0 -> input available IRQ
 		call slow_out
 
 		inc dx				; DX -> FCR/IIR
@@ -262,8 +262,7 @@ pc_serial:	call getint
 
 		inc dx
 		inc dx				; DX -> MCR
-		in al,dx
-		or al,[FlowOutput]		; Assert bits
+		mov al,[FlowOutput]		; Assert bits
 		call slow_out
 
 		; Show some life
diff --git a/core/pxeidle.inc b/core/pxeidle.inc
index 84a201f3..1d458810 100644
--- a/core/pxeidle.inc
+++ b/core/pxeidle.inc
@@ -1,6 +1,7 @@
 ;; -*- fundamental -*- ---------------------------------------------------
 ;;
 ;;   Copyright 2008 H. Peter Anvin - All Rights Reserved
+;;   Copyright 2009 Intel Corporation; author: H. Peter Anvin
 ;;
 ;;   This program is free software; you can redistribute it and/or modify
 ;;   it under the terms of the GNU General Public License as published by
@@ -48,7 +49,7 @@ pxe_detect_nic_type:
 		ret
 
 .found_device:
-		and byte [feature_flags],~2
+		mov word [IdleHook],check_for_arp
 		jmp .done
 
 ;;
@@ -90,3 +91,34 @@ pxenv_get_nic_type:
 .sdid:		resw 1
 
 		section .text16
+;
+; Call the receive loop while idle.  This is done mostly so we can respond to
+; ARP messages, but perhaps in the future this can be used to do network
+; console.
+;
+; hpa sez: people using automatic control on the serial port get very
+; unhappy if we poll for ARP too often (the PXE stack is pretty slow,
+; typically.)  Therefore, only poll if at least 4 BIOS timer ticks have
+; passed since the last poll, and reset this when a character is
+; received (call reset_idle).
+;
+; Note: we only do this if pxe_detect_nic_type has set the IdleHook
+; to point to this routine.
+;
+check_for_arp:
+		pushad
+		mov di,packet_buf
+		mov [pxe_udp_read_pkt.buffer],di
+		mov [pxe_udp_read_pkt.buffer+2],ds
+		mov word [pxe_udp_read_pkt.buffersize],packet_buf_size
+		mov eax,[MyIP]
+		mov [pxe_udp_read_pkt.dip],eax
+		mov word [pxe_udp_read_pkt.lport],htons(9)	; discard port
+		mov di,pxe_udp_read_pkt
+		mov bx,PXENV_UDP_READ
+		call pxenv
+		; Ignore result...
+		pop es
+		pop ds
+		popad
+		ret
diff --git a/core/pxelinux.asm b/core/pxelinux.asm
index f44a081f..4352903d 100644
--- a/core/pxelinux.asm
+++ b/core/pxelinux.asm
@@ -53,24 +53,6 @@ TFTP_BLOCKSIZE	equ (1 << TFTP_BLOCKSIZE_LG2)
 SECTOR_SHIFT	equ TFTP_BLOCKSIZE_LG2
 SECTOR_SIZE	equ TFTP_BLOCKSIZE
 
-%define HAVE_IDLE 1			; idle is not a noop
-
-%if HAVE_IDLE
-%macro	RESET_IDLE 0
-	call reset_idle
-%endmacro
-%macro	DO_IDLE 0
-	call check_for_arp
-%endmacro
-%else
-%macro	RESET_IDLE 0
-	; Nothing
-%endmacro
-%macro	DO_IDLE 0
-	; Nothing
-%endmacro
-%endif
-
 ;
 ; TFTP operation codes
 ;
@@ -195,7 +177,6 @@ PXEStack	resd 1			; Saved stack during PXE call
 RebootTime	resd 1			; Reboot timeout, if set by option
 StrucPtr	resd 1			; Pointer to PXENV+ or !PXE structure
 APIVer		resw 1			; PXE API version found
-IdleTimer	resw 1			; Time to check for ARP?
 LocalBootType	resw 1			; Local boot return code
 RealBaseMem	resw 1			; Amount of DOS memory after freeing
 OverLoad	resb 1			; Set if DHCP packet uses "overloading"
@@ -620,7 +601,7 @@ udp_init:
 ; Detect NIC type and initialize the idle mechanism
 ;
 		call pxe_detect_nic_type
-		RESET_IDLE
+		call reset_idle
 
 ;
 ; Now we're all set to start with our *real* business.	First load the
@@ -2547,64 +2528,6 @@ genipopt:
 		popad
 		ret
 
-;
-; Call the receive loop while idle.  This is done mostly so we can respond to
-; ARP messages, but perhaps in the future this can be used to do network
-; console.
-;
-; hpa sez: people using automatic control on the serial port get very
-; unhappy if we poll for ARP too often (the PXE stack is pretty slow,
-; typically.)  Therefore, only poll if at least 4 BIOS timer ticks have
-; passed since the last poll, and reset this when a character is
-; received (RESET_IDLE).
-;
-; Note: we only do this if pxe_detect_nic_type has cleared the
-; "idle is noop" bit in feature_flags.
-;
-%if HAVE_IDLE
-
-reset_idle:
-		push ax
-		mov ax,[cs:BIOS_timer]
-		mov [cs:IdleTimer],ax
-		pop ax
-		ret
-
-check_for_arp:
-		test byte [cs:feature_flags],2
-		jnz .ret
-		push ax
-		mov ax,[cs:BIOS_timer]
-		sub ax,[cs:IdleTimer]
-		cmp ax,4
-		pop ax
-		jae .need_poll
-.ret:		ret
-.need_poll:	pushad
-		push ds
-		push es
-		mov ax,cs
-		mov ds,ax
-		mov es,ax
-		mov di,packet_buf
-		mov [pxe_udp_read_pkt.buffer],di
-		mov [pxe_udp_read_pkt.buffer+2],ds
-		mov word [pxe_udp_read_pkt.buffersize],packet_buf_size
-		mov eax,[MyIP]
-		mov [pxe_udp_read_pkt.dip],eax
-		mov word [pxe_udp_read_pkt.lport],htons(9)	; discard port
-		mov di,pxe_udp_read_pkt
-		mov bx,PXENV_UDP_READ
-		call pxenv
-		; Ignore result...
-		pop es
-		pop ds
-		popad
-		RESET_IDLE
-		ret
-
-%endif ; HAVE_IDLE
-
 ; -----------------------------------------------------------------------------
 ;  Common modules
 ; -----------------------------------------------------------------------------
@@ -2615,7 +2538,7 @@ writestr_early	equ writestr
 %include "writehex.inc"		; Hexadecimal output
 %include "rawcon.inc"		; Console I/O w/o using the console functions
 %include "dnsresolv.inc"	; DNS resolver
-%include "pxeidle.inc"		; Idle mechanism
+%include "pxeidle.inc"		; PXE-specific idle mechanism
 
 ; -----------------------------------------------------------------------------
 ;  Begin data section
diff --git a/core/ui.inc b/core/ui.inc
index 5ac8d8c2..4a97e7d3 100644
--- a/core/ui.inc
+++ b/core/ui.inc
@@ -526,7 +526,7 @@ kernel_corrupt: mov si,err_notkernel
 ;
 getchar_timeout:
 		call vgashowcursor
-		RESET_IDLE
+		call reset_idle
 
 .loop:
 		push word [BIOS_timer]
@@ -535,7 +535,7 @@ getchar_timeout:
 		pop ax
 		cmp ax,[BIOS_timer]		; Has the timer advanced?
 		je .loop
-		DO_IDLE
+		call do_idle
 
 		dec dword [ThisKbdTo]
 		jz .timeout
diff --git a/doc/syslinux.txt b/doc/syslinux.txt
index 94141415..f654bffd 100644
--- a/doc/syslinux.txt
+++ b/doc/syslinux.txt
@@ -339,6 +339,7 @@ SERIAL port [[baudrate] flowcontrol]
 	"flowcontrol" is a combination of the following bits:
 	0x001 - Assert DTR
 	0x002 - Assert RTS
+	0x008 - Enable interrupts
 	0x010 - Wait for CTS assertion
 	0x020 - Wait for DSR assertion
 	0x040 - Wait for RI assertion
@@ -366,6 +367,17 @@ SERIAL port [[baudrate] flowcontrol]
 	ports detected by the BIOS.  They may or may not correspond to
 	the legacy port values 0x3F8, 0x2F8, 0x3E8, 0x2E8.
 
+	Enabling interrupts (setting the 0x008 bit) may give better
+	responsiveness without setting the NOHALT option, but could
+	potentially cause problems with buggy BIOSes.
+
+NOHALT flag_val
+	If flag_val is 1, don't halt the processor while idle.
+	Halting the processor while idle significantly reduces the
+	power consumption, but can cause poor responsiveness to the
+	serial console, especially when using scripts to drive the
+	serial console, as opposed to human interaction.
+
 CONSOLE flag_val
 	If flag_val is 0, disable output to the normal video console.
 	If flag_val is 1, enable output to the video console (this is