2005-07-17 Yoshinori Okuji <okuji@enbug.org>

	* kern/i386/pc/startup.S (gate_a20_try_system_control_port_a):
	When turning off Gate A20, skip the check and return immediately,
	because this is not fatal usually.

diff --git a/ChangeLog b/ChangeLog
index 70771a39715bd103429117a7861b61e7ade02d26..63a4c859932433b8dbe0b24f36ca42a7945a9cfd 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2005-07-17  Yoshinori Okuji  <okuji@enbug.org>
+
+       * kern/i386/pc/startup.S (gate_a20_try_system_control_port_a):
+       When turning off Gate A20, skip the check and return immediately,
+       because this is not fatal usually.
+
 2005-07-17  Yoshinori Okuji  <okuji@enbug.org>
 
        * conf/i386-pc.rmk (pxeboot_img_LDFLAGS): The text address should

diff --git a/kern/i386/pc/startup.S b/kern/i386/pc/startup.S
index 177c86501d6102f20cadaec33ce60abc5266e35f..a04f90f2ac00cd0734d2d729529c16a97f10a354 100644 (file)
--- a/kern/i386/pc/startup.S
+++ b/kern/i386/pc/startup.S
@@ -463,12 +463,17 @@ gate_a20_try_system_control_port_a:
        jz      6f
        orb     $0x02, %al
 6:     outb    $0x92
-       
+
+       /* When turning off Gate A20, do not check the state strictly,
+          because a failure is not fatal usually, and Gate A20 is always
+          on some modern machines.  */
+       testb   %dl, %dl
+       jz      7f      
        call    gate_a20_check_state
        cmpb    %al, %dl
        /* everything failed, so restart from the beginning */
        jnz     gate_a20_try_bios
-       ret
+7:     ret
        
 gate_a20_check_state:
        /* iterate the checking for a while */