linux-kernel - [PATCH] pps: events reporting fix up.

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Message-Id: <1257504596-27781-2-git-send-email-giometti@linux.it>
Date:	Fri,  6 Nov 2009 11:49:56 +0100
From:	Rodolfo Giometti <giometti@...ux.it>
To:	linux-kernel@...r.kernel.org
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Rodolfo Giometti <giometti@...ux.it>
Subject: [PATCH] pps: events reporting fix up.

PPS events must be recorded according to PPS's mode settings.

If a process asks for (i.e.) capture-assert events only, when the PPS
client calls the pps_event() function to save the current PPS event,
we should verify the event type and then discard unwanted ones.

Also, without this patch userland processes waiting for a specific PPS
event (assert or clear but not both) may be awakened at wrong time.

Signed-off-by: Rodolfo Giometti <giometti@...ux.it>
Tested-by: William S. Brasher <billb958@...r.net>
Tested-by: Reg Clemens <clemens@....com>
---
 drivers/pps/kapi.c |   20 +++++++++++++++-----
 1 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
index 35a0b19..2d414e2 100644
--- a/drivers/pps/kapi.c
+++ b/drivers/pps/kapi.c
@@ -271,6 +271,7 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
 {
 	struct pps_device *pps;
 	unsigned long flags;
+	int captured = 0;
 
 	if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
 		printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
@@ -293,7 +294,8 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
 
 	/* Check the event */
 	pps->current_mode = pps->params.mode;
-	if (event & PPS_CAPTUREASSERT) {
+	if ((event & PPS_CAPTUREASSERT) &
+			(pps->params.mode & PPS_CAPTUREASSERT)) {
 		/* We have to add an offset? */
 		if (pps->params.mode & PPS_OFFSETASSERT)
 			pps_add_offset(ts, &pps->params.assert_off_tu);
@@ -303,8 +305,11 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
 		pps->assert_sequence++;
 		pr_debug("capture assert seq #%u for source %d\n",
 			pps->assert_sequence, source);
+
+		captured = ~0;
 	}
-	if (event & PPS_CAPTURECLEAR) {
+	if ((event & PPS_CAPTURECLEAR) &
+			(pps->params.mode & PPS_CAPTURECLEAR)) {
 		/* We have to add an offset? */
 		if (pps->params.mode & PPS_OFFSETCLEAR)
 			pps_add_offset(ts, &pps->params.clear_off_tu);
@@ -314,12 +319,17 @@ void pps_event(int source, struct pps_ktime *ts, int event, void *data)
 		pps->clear_sequence++;
 		pr_debug("capture clear seq #%u for source %d\n",
 			pps->clear_sequence, source);
+
+		captured = ~0;
 	}
 
-	pps->go = ~0;
-	wake_up_interruptible(&pps->queue);
+	/* Wake up iif captured somthing */
+	if (captured) {
+		pps->go = ~0;
+		wake_up_interruptible(&pps->queue);
 
-	kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
+		kill_fasync(&pps->async_queue, SIGIO, POLL_IN);
+	}
 
 	spin_unlock_irqrestore(&pps->lock, flags);
 
-- 
1.6.0.4

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