upstream: [media] dib0090: Fix the sleep time at the state machine

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().

Acked-By: Patrick Boettcher <pboettcher@kernellabs.com>
Backports http://git.linuxtv.org/cgit.cgi/media_tree.git/commit/?id=0de04ca1dc0b
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --git a/drivers/media/dvb-frontends/dib0090.c b/drivers/media/dvb-frontends/dib0090.c
index 3ee22ff..68e2af2 100644 (file)
--- a/drivers/media/dvb-frontends/dib0090.c
+++ b/drivers/media/dvb-frontends/dib0090.c
@@ -2557,10 +2557,19 @@ static int dib0090_set_params(struct dvb_frontend *fe)
 
        do {
                ret = dib0090_tune(fe);
-               if (ret != FE_CALLBACK_TIME_NEVER)
-                       msleep(ret / 10);
-               else
+               if (ret == FE_CALLBACK_TIME_NEVER)
                        break;
+
+               /*
+                * Despite dib0090_tune 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 and use usleep_range() instead of msleep().
+                */
+               ret = 10 * (ret + 99)/100;
+               usleep_range(ret * 1000, (ret + 1) * 1000);
        } while (state->tune_state != CT_TUNER_STOP);
 
        return 0;