Rate-limit ARP calls to avoid screwing over people doing automatic

control via the serial port.

diff --git a/conio.inc b/conio.inc
index 58c7e3a..535028b 100644 (file)
--- a/conio.inc
+++ b/conio.inc
@@ -319,6 +319,7 @@ pollchar:
 ; getchar: Read a character from keyboard or serial port
 ;
 getchar:
+               RESET_IDLE
 .again:
                DO_IDLE
                mov ah,1                ; Poll keyboard

diff --git a/isolinux.asm b/isolinux.asm
index fd67d2e..086bc5e 100644 (file)
--- a/isolinux.asm
+++ b/isolinux.asm
@@ -43,6 +43,9 @@ SECTORSIZE    equ (1 << SECTORSIZE_LG2)
 ;
 ; This is what we need to do when idle
 ;
+%macro RESET_IDLE 0
+       ; Nothing
+%endmacro
 %macro DO_IDLE 0
        ; Nothing
 %endmacro

diff --git a/ldlinux.asm b/ldlinux.asm
index 745aec2..4a9d475 100644 (file)
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -48,6 +48,9 @@ retry_count   equ 6                   ; How patient are we with the disk?
 ;
 ; This is what we need to do when idle
 ;
+%macro RESET_IDLE 0
+       ; Nothing
+%endmacro
 %macro DO_IDLE 0
        ; Nothing
 %endmacro

diff --git a/pxelinux.asm b/pxelinux.asm
index 0822992..8f628a2 100644 (file)
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -55,6 +55,9 @@ TFTP_BLOCKSIZE        equ (1 << TFTP_BLOCKSIZE_LG2)
 ;
 ; This is what we need to do when idle
 ;
+%macro RESET_IDLE 0
+       call reset_idle
+%endmacro
 %macro DO_IDLE 0
        call check_for_arp
 %endmacro
@@ -264,6 +267,7 @@ IPOptionLen resw 1                  ; Length of IPOption
 LocalBootType  resw 1                  ; Local boot return code
 RealBaseMem    resw 1                  ; Amount of DOS memory after freeing
 APIVer         resw 1                  ; PXE API version found
+IdleTimer      resw 1                  ; Time to check for ARP?
 TextAttrBX      equ $
 TextAttribute   resb 1                 ; Text attribute for message file
 TextPage        resb 1                 ; Active display page
@@ -2293,8 +2297,28 @@ genipopt:
 ; 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).
+;
+reset_idle:
+               push ax
+               mov ax,[cs:BIOS_timer]
+               mov [cs:IdleTimer],ax
+               pop ax
+               ret
+
 check_for_arp:
-               pushad
+               push ax
+               mov ax,[cs:BIOS_timer]
+               sub ax,[cs:IdleTimer]
+               cmp ax,4
+               pop ax
+               jae .need_poll
+               ret
+.need_poll:    pushad
                push ds
                push es
                mov ax,cs
@@ -2315,6 +2339,7 @@ check_for_arp:
                pop es
                pop ds
                popad
+               RESET_IDLE
                ret
 
 ; -----------------------------------------------------------------------------

diff --git a/ui.inc b/ui.inc
index c11c088..528d563 100644 (file)
--- a/ui.inc
+++ b/ui.inc
@@ -44,6 +44,7 @@ clear_buffer: mov ah,1                        ; Check for pending char
                jmp short clear_buffer
 get_char_time: 
                call vgashowcursor
+               RESET_IDLE
                mov cx,[KbdTimeOut]
                and cx,cx
                jz get_char                     ; Timeout == 0 -> no timeout