[PATCH] APM Screen Blanking fix

- Fix screen blanking on BIOSes that return APM_NOT_ENGAGED when APM enabled
  screen blanking is not turned on.

  The original code only tried to set the state on device 0x100, and then
  0x1FF, and I added 0x101 to the mix too.

- Clean up logic in apm_console_blank().

- Prevent the error message from printing out twice.

Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 14 insertions, 13 deletions

diff --git a/arch/i386/kernel/apm.c b/arch/i386/kernel/apm.c
index d0b488056cc4..2d793d4aef1a 100644
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -1064,22 +1064,23 @@ static int apm_engage_power_management(u_short device, int enable)
  
 static int apm_console_blank(int blank)
 {
-        int     error;
-        u_short state;
+        int error, i;
+        u_short state;
+        static const u_short dev[3] = { 0x100, 0x1FF, 0x101 };
 
         state = blank ? APM_STATE_STANDBY : APM_STATE_READY;
-        /* Blank the first display device */
-        error = set_power_state(0x100, state);
-        if ((error != APM_SUCCESS) && (error != APM_NO_ERROR)) {
-                /* try to blank them all instead */
-                error = set_power_state(0x1ff, state);
-                if ((error != APM_SUCCESS) && (error != APM_NO_ERROR))
-                        /* try to blank device one instead */
-                        error = set_power_state(0x101, state);
+
+        for (i = 0; i < ARRAY_SIZE(dev); i++) {
+                error = set_power_state(dev[i], state);
+
+                if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
+                        return 1;
+
+                if (error == APM_NOT_ENGAGED)
+                        break;
         }
-        if ((error == APM_SUCCESS) || (error == APM_NO_ERROR))
-                return 1;
-        if (error == APM_NOT_ENGAGED) {
+
+        if (error == APM_NOT_ENGAGED && state != APM_STATE_READY) {
                 static int tried;
                 int eng_error;
                 if (tried++ == 0) {