V4L/DVB (12465): cx88: High resolution timer for Remote Controls

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@wp.pl>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 17 insertions, 8 deletions

diff --git a/drivers/media/video/cx88/cx88-input.c b/drivers/media/video/cx88/cx88-input.c
index 0abc3210072b..79c4408a6171 100644
--- a/drivers/media/video/cx88/cx88-input.c
+++ b/drivers/media/video/cx88/cx88-input.c
@@ -23,7 +23,7 @@
  */
 
 #include <linux/init.h>
-#include <linux/delay.h>
+#include <linux/hrtimer.h>
 #include <linux/input.h>
 #include <linux/pci.h>
 #include <linux/module.h>
@@ -48,7 +48,7 @@ struct cx88_IR {
 
         /* poll external decoder */
         int polling;
-        struct delayed_work work;
+        struct hrtimer timer;
         u32 gpio_addr;
         u32 last_gpio;
         u32 mask_keycode;
@@ -144,19 +144,28 @@ static void cx88_ir_handle_key(struct cx88_IR *ir)
         }
 }
 
-static void cx88_ir_work(struct work_struct *work)
+static enum hrtimer_restart cx88_ir_work(struct hrtimer *timer)
 {
-        struct cx88_IR *ir = container_of(work, struct cx88_IR, work.work);
+        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) {
-                INIT_DELAYED_WORK(&ir->work, cx88_ir_work);
-                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;
@@ -173,7 +182,7 @@ void cx88_ir_stop(struct cx88_core *core, struct cx88_IR *ir)
         }
 
         if (ir->polling)
-                cancel_delayed_work_sync(&ir->work);
+                hrtimer_cancel(&ir->timer);
 }
 
 /* ---------------------------------------------------------------------- */