[PATCH] cx88: High resolution timer for Remote Controls

[AH <andrzej.hajda@xxxxx>]

Patch solves problem of missed keystrokes on some remote controls,
as reported on http://bugzilla.kernel.org/show_bug.cgi?id=9637 .

---
Signed-off-by: Andrzej Hajda <andrzej.hajda@xxxxx <mailto:andrzej.hajda@xxxxx>>
Acked-by: Jean Delvare <khali@xxxxxxxxxxxx <mailto:khali@xxxxxxxxxxxx>>

---
diff -r 315bc4b65b4f linux/drivers/media/video/cx88/cx88-input.c
--- a/linux/drivers/media/video/cx88/cx88-input.c    Sun May 17 12:28:55 
2009 +0000
+++ b/linux/drivers/media/video/cx88/cx88-input.c    Sat May 30 14:16:24 
2009 +0200
@@ -23,10 +23,10 @@
 */

#include <linux/init.h>
-#include <linux/delay.h>
#include <linux/input.h>
#include <linux/pci.h>
#include <linux/module.h>
+#include <linux/hrtimer.h>

#include "compat.h"
#include "cx88.h"
@@ -49,7 +49,7 @@ struct cx88_IR {

    /* poll external decoder */
    int polling;
-    struct delayed_work work;
+    struct hrtimer timer;
    u32 gpio_addr;
    u32 last_gpio;
    u32 mask_keycode;
@@ -144,31 +144,27 @@ static void cx88_ir_handle_key(struct cx
    }
}

-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
-static void cx88_ir_work(void *data)
-#else
-static void cx88_ir_work(struct work_struct *work)
-#endif
+enum hrtimer_restart cx88_ir_work(struct hrtimer *timer)
{
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
-    struct cx88_IR *ir = data;
-#else
-    struct cx88_IR *ir = container_of(work, struct cx88_IR, work.work);
-#endif
+    unsigned long missed;
+    struct cx88_IR *ir = container_of(timer, struct cx88_IR, timer);

    cx88_ir_handle_key(ir);
-    schedule_delayed_work(&ir->work, msecs_to_jiffies(ir->polling));
+    missed = hrtimer_forward_now(&ir->timer,
+                     ktime_set(0, ir->polling * 1000000));
+    if (missed > 1)
+        ir_dprintk("Missed ticks %ld\n", missed - 1);
+
+    return HRTIMER_RESTART;
}

void cx88_ir_start(struct cx88_core *core, struct cx88_IR *ir)
{
    if (ir->polling) {
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
-        INIT_DELAYED_WORK(&ir->work, cx88_ir_work, ir);
-#else
-        INIT_DELAYED_WORK(&ir->work, cx88_ir_work);
-#endif
-        schedule_delayed_work(&ir->work, 0);
+        hrtimer_init(&ir->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+        ir->timer.function = cx88_ir_work;
+        hrtimer_start(&ir->timer, ktime_set(0, ir->polling * 1000000),
+                  HRTIMER_MODE_REL);
    }
    if (ir->sampling) {
        core->pci_irqmask |= PCI_INT_IR_SMPINT;
@@ -185,7 +181,7 @@ void cx88_ir_stop(struct cx88_core *core
    }

    if (ir->polling)
-        cancel_delayed_work_sync(&ir->work);
+        hrtimer_cancel(&ir->timer);
}

/* 
---------------------------------------------------------------------- */

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