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[[PATCH,v2] 09/14] dib8000: Fix the sleep time at the state machine

Message ID 1404494140-17777-10-git-send-email-m.chehab@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mauro Carvalho Chehab July 4, 2014, 5:15 p.m. UTC 
msleep() is not too precise: its precision depends on the
HZ config. As the driver selects precise timings for the
state machine, change it to usleep_range().

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---
 drivers/media/dvb-frontends/dib8000.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)
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Patch

diff --git a/drivers/media/dvb-frontends/dib8000.c b/drivers/media/dvb-frontends/dib8000.c
index e4da545680b6..9f40af588441 100644
--- a/drivers/media/dvb-frontends/dib8000.c
+++ b/drivers/media/dvb-frontends/dib8000.c
@@ -3607,10 +3607,19 @@  static int dib8000_set_frontend(struct dvb_frontend *fe)
 			else if ((time_slave != FE_CALLBACK_TIME_NEVER) && (time_slave > time))
 				time = time_slave;
 		}
-		if (time != FE_CALLBACK_TIME_NEVER)
-			msleep(time / 10);
-		else
+		if (time == FE_CALLBACK_TIME_NEVER)
 			break;
+
+		/*
+		 * Despite dib8000_agc_startup returns time at a 0.1 ms range,
+		 * the actual sleep time depends on CONFIG_HZ. The worse case
+		 * is when CONFIG_HZ=100. In such case, the minimum granularity
+		 * is 10ms. On some real field tests, the tuner sometimes don't
+		 * lock when this timer is lower than 10ms. So, enforce a 10ms
+		 * granularity.
+		 */
+		time = 10 * (time + 99)/100;
+		usleep_range(time * 1000, (time + 1) * 1000);
 		exit_condition = 1;
 		for (index_frontend = 0; (index_frontend < MAX_NUMBER_OF_FRONTENDS) && (state->fe[index_frontend] != NULL); index_frontend++) {
 			if (dib8000_get_tune_state(state->fe[index_frontend]) != CT_AGC_STOP) {