Input: wriston - reduce polling frequency

[pandora-kernel.git] / drivers / input / misc / wistron_btns.c

diff --git a/drivers/input/misc/wistron_btns.c b/drivers/input/misc/wistron_btns.c
index 961aad7..320262a 100644 (file)
--- a/drivers/input/misc/wistron_btns.c
+++ b/drivers/input/misc/wistron_btns.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/input.h>
 #include <linux/interrupt.h>
+#include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/mc146818rtc.h>
 #include <linux/module.h>
@@ -37,9 +38,10 @@
  */
 #define MAX_POLL_ITERATIONS 64
 
-#define POLL_FREQUENCY 10 /* Number of polls per second */
+#define POLL_FREQUENCY 2 /* Number of polls per second when idle */
+#define POLL_FREQUENCY_BURST 10 /* Polls per second when a key was recently pressed */
 
-#if POLL_FREQUENCY > HZ
+#if POLL_FREQUENCY_BURST > HZ
 #error "POLL_FREQUENCY too high"
 #endif
 
@@ -1079,6 +1081,8 @@ static void handle_key(u8 code)
 
 static void poll_bios(unsigned long discard)
 {
+       static unsigned long jiffies_last_press;
+       unsigned long jiffies_now = jiffies;
        u8 qlen;
        u16 val;
 
@@ -1087,11 +1091,17 @@ static void poll_bios(unsigned long discard)
                if (qlen == 0)
                        break;
                val = bios_pop_queue();
-               if (val != 0 && !discard)
+               if (val != 0 && !discard) {
                        handle_key((u8)val);
+                       jiffies_last_press = jiffies_now;
+               }
        }
 
-       mod_timer(&poll_timer, jiffies + HZ / POLL_FREQUENCY);
+       /* Increase precision if user is currently pressing keys (< 2s ago) */
+       if (time_after(jiffies_last_press, jiffies_now - (HZ * 2)))
+               mod_timer(&poll_timer, jiffies_now + HZ / POLL_FREQUENCY_BURST);
+       else
+               mod_timer(&poll_timer, jiffies_now + HZ / POLL_FREQUENCY);
 }
 
 static int __devinit wistron_probe(struct platform_device *dev)