[media] DVB: stb0899: speed up getting BER values

stb0899_read_ber() takes 500ms (half a second!) to deliver the current
BER value. Apparently it takes 5 subsequent readings, with a 100ms pause
between them (and even before the first one). This is a real performance
brake if an application freqeuently reads the BER of several devices.
The attached patch reduces this to a single reading, with no more pausing.
I didn't observe any negative side effects of this change.

Signed-off-by: Klaus Schmidinger <Klaus.Schmidinger@tvdr.de>
Cc: Manu Abraham <abraham.manu@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/dvb/frontends/stb0899_drv.c b/drivers/media/dvb/frontends/stb0899_drv.c
index 8b0dc74a3298c8ec03d99cf40b1faa2be0e8a2ba..5d7f8a9b451b8ec93fc596a6d813004b8866cd87 100644 (file)
--- a/drivers/media/dvb/frontends/stb0899_drv.c
+++ b/drivers/media/dvb/frontends/stb0899_drv.c
@@ -1129,7 +1129,6 @@ static int stb0899_read_ber(struct dvb_frontend *fe, u32 *ber)
        struct stb0899_internal *internal       = &state->internal;
 
        u8  lsb, msb;
-       u32 i;
 
        *ber = 0;
 
@@ -1137,14 +1136,9 @@ static int stb0899_read_ber(struct dvb_frontend *fe, u32 *ber)
        case SYS_DVBS:
        case SYS_DSS:
                if (internal->lock) {
-                       /* average 5 BER values */
-                       for (i = 0; i < 5; i++) {
-                               msleep(100);
-                               lsb = stb0899_read_reg(state, STB0899_ECNT1L);
-                               msb = stb0899_read_reg(state, STB0899_ECNT1M);
-                               *ber += MAKEWORD16(msb, lsb);
-                       }
-                       *ber /= 5;
+                       lsb = stb0899_read_reg(state, STB0899_ECNT1L);
+                       msb = stb0899_read_reg(state, STB0899_ECNT1M);
+                       *ber = MAKEWORD16(msb, lsb);
                        /* Viterbi Check        */
                        if (STB0899_GETFIELD(VSTATUS_PRFVIT, internal->v_status)) {
                                /* Error Rate           */
@@ -1157,13 +1151,9 @@ static int stb0899_read_ber(struct dvb_frontend *fe, u32 *ber)
                break;
        case SYS_DVBS2:
                if (internal->lock) {
-                       /* Average 5 PER values */
-                       for (i = 0; i < 5; i++) {
-                               msleep(100);
-                               lsb = stb0899_read_reg(state, STB0899_ECNT1L);
-                               msb = stb0899_read_reg(state, STB0899_ECNT1M);
-                               *ber += MAKEWORD16(msb, lsb);
-                       }
+                       lsb = stb0899_read_reg(state, STB0899_ECNT1L);
+                       msb = stb0899_read_reg(state, STB0899_ECNT1M);
+                       *ber = MAKEWORD16(msb, lsb);
                        /* ber = ber * 10 ^ 7   */
                        *ber *= 10000000;
                        *ber /= (-1 + (1 << (4 + 2 * STB0899_GETFIELD(NOE, internal->err_ctrl))));