4 files changed, 42 insertions, 18 deletions

diff --git a/drivers/media/video/cx18/cx18-driver.c b/drivers/media/video/cx18/cx18-driver.c
index 3079e466e6e7..8ef11d578b8d 100644
--- a/drivers/media/video/cx18/cx18-driver.c
+++ b/drivers/media/video/cx18/cx18-driver.c
@@ -187,7 +187,7 @@ MODULE_VERSION(CX18_VERSION);
 /* Generic utility functions */
 int cx18_msleep_timeout(unsigned int msecs, int intr)
 {
-        int timeout = msecs_to_jiffies(msecs);
+        long int timeout = msecs_to_jiffies(msecs);
         int sig;
 
         do {
diff --git a/drivers/media/video/cx18/cx18-driver.h b/drivers/media/video/cx18/cx18-driver.h
index e2ec15549783..ce76806759ec 100644
--- a/drivers/media/video/cx18/cx18-driver.h
+++ b/drivers/media/video/cx18/cx18-driver.h
@@ -360,6 +360,12 @@ struct cx18_mmio_stats {
         atomic_t retried_read[CX18_MAX_MMIO_RD_RETRIES+1];
 };
 
+#define CX18_MAX_MB_ACK_DELAY 100
+
+struct cx18_mbox_stats {
+        atomic_t mb_ack_delay[CX18_MAX_MB_ACK_DELAY+1];
+};
+
 /* Struct to hold info about cx18 cards */
 struct cx18 {
         int num;                /* board number, -1 during init! */
@@ -452,6 +458,7 @@ struct cx18 {
 
         /* Statistics */
         struct cx18_mmio_stats mmio_stats;
+        struct cx18_mbox_stats mbox_stats;
 
         /* v4l2 and User settings */
 
diff --git a/drivers/media/video/cx18/cx18-io.c b/drivers/media/video/cx18/cx18-io.c
index 0ad8dea3e600..48a8adc83c2f 100644
--- a/drivers/media/video/cx18/cx18-io.c
+++ b/drivers/media/video/cx18/cx18-io.c
@@ -37,6 +37,10 @@ void cx18_log_statistics(struct cx18 *cx)
         for (i = 0; i <= CX18_MAX_MMIO_RD_RETRIES; i++)
                 CX18_DEBUG_INFO("retried_read[%d] = %d\n", i,
                                 atomic_read(&cx->mmio_stats.retried_read[i]));
+        for (i = 0; i <= CX18_MAX_MB_ACK_DELAY; i++)
+                if (atomic_read(&cx->mbox_stats.mb_ack_delay[i]))
+                        CX18_DEBUG_INFO("mb_ack_delay[%d] = %d\n", i,
+                                  atomic_read(&cx->mbox_stats.mb_ack_delay[i]));
         return;
 }
 
diff --git a/drivers/media/video/cx18/cx18-mailbox.c b/drivers/media/video/cx18/cx18-mailbox.c
index 0de4b9a7bbca..35f7188d4d3b 100644
--- a/drivers/media/video/cx18/cx18-mailbox.c
+++ b/drivers/media/video/cx18/cx18-mailbox.c
@@ -118,6 +118,12 @@ long cx18_mb_ack(struct cx18 *cx, const struct cx18_mailbox *mb, int rpu)
         return 0;
 }
 
+static void cx18_api_log_ack_delay(struct cx18 *cx, int msecs)
+{
+        if (msecs > CX18_MAX_MB_ACK_DELAY)
+                msecs = CX18_MAX_MB_ACK_DELAY;
+        atomic_inc(&cx->mbox_stats.mb_ack_delay[msecs]);
+}
 
 static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
 {
@@ -127,8 +133,7 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
         u32 __iomem *xpu_state;
         wait_queue_head_t *waitq;
         struct mutex *mb_lock;
-        int timeout = 100;
-        long unsigned int j, ret;
+        long int timeout, ret;
         int i;
 
         if (info == NULL) {
@@ -176,18 +181,18 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
          */
         state = cx18_readl(cx, xpu_state);
         req = cx18_readl(cx, &mb->request);
-        j = msecs_to_jiffies(timeout);
+        timeout = msecs_to_jiffies(20); /* 1 field at 50 Hz vertical refresh */
         ret = wait_event_timeout(*waitq,
                                  (ack = cx18_readl(cx, &mb->ack)) == req,
-                                 j);
+                                 timeout);
         if (req != ack) {
                 /* waited long enough, make the mbox "not busy" from our end */
                 cx18_writel(cx, req, &mb->ack);
                 CX18_ERR("mbox was found stuck busy when setting up for %s; "
                          "clearing busy and trying to proceed\n", info->name);
-        } else if (ret != j)
+        } else if (ret != timeout)
                 CX18_DEBUG_API("waited %u usecs for busy mbox to be acked\n",
-                               jiffies_to_usecs(j-ret));
+                               jiffies_to_usecs(timeout-ret));
 
         /* Build the outgoing mailbox */
         req = ((req & 0xfffffffe) == 0xfffffffe) ? 1 : req + 1;
@@ -199,24 +204,28 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
         cx18_writel(cx, req, &mb->request);
         cx18_writel(cx, req - 1, &mb->ack); /* ensure ack & req are distinct */
 
-        /* Notify the XPU and wait for it to send an Ack back */
-        if (info->flags & API_FAST)
-                timeout /= 2;
-        j = msecs_to_jiffies(timeout);
+        /*
+         * Notify the XPU and wait for it to send an Ack back
+         * 21 ms = ~ 0.5 frames at a frame rate of 24 fps
+         * 42 ms = ~ 1 frame at a frame rate of 24 fps
+         */
+        timeout = msecs_to_jiffies((info->flags & API_FAST) ? 21 : 42);
 
         CX18_DEBUG_HI_IRQ("sending interrupt SW1: %x to send %s\n",
                           irq, info->name);
         cx18_write_reg_expect(cx, irq, SW1_INT_SET, irq, irq);
 
-        ret = wait_event_interruptible_timeout(
+        ret = wait_event_timeout(
                        *waitq,
                        cx18_readl(cx, &mb->ack) == cx18_readl(cx, &mb->request),
-                       j);
+                       timeout);
         if (ret == 0) {
                 /* Timed out */
                 mutex_unlock(mb_lock);
-                CX18_ERR("sending %s timed out waiting for RPU "
-                         "acknowledgement\n", info->name);
+                i = jiffies_to_msecs(timeout);
+                cx18_api_log_ack_delay(cx, i);
+                CX18_WARN("sending %s timed out waiting %d msecs for RPU "
+                          "acknowledgement\n", info->name, i);
                 return -EINVAL;
         } else if (ret < 0) {
                 /* Interrupted */
@@ -224,9 +233,13 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
                 CX18_WARN("sending %s was interrupted waiting for RPU"
                           "acknowledgement\n", info->name);
                 return -EINTR;
-        } else if (ret != j)
-                CX18_DEBUG_HI_API("waited %u usecs for %s to be acked\n",
-                                  jiffies_to_usecs(j-ret), info->name);
+        }
+
+        i = jiffies_to_msecs(timeout-ret);
+        cx18_api_log_ack_delay(cx, i);
+        if (ret != timeout)
+                CX18_DEBUG_HI_API("waited %u msecs for %s to be acked\n",
+                                  i, info->name);
 
         /* Collect data returned by the XPU */
         for (i = 0; i < MAX_MB_ARGUMENTS; i++)