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 <[email protected]>
Klaus
--- a/linux/drivers/media/dvb/frontends/stb0899_drv.c 2012-04-23 15:10:35.994008188 +0200
+++ a/linux/drivers/media/dvb/frontends/stb0899_drv.c 2012-04-23 15:29:40.544837905 +0200
@@ -1135,7 +1135,6 @@
struct stb0899_internal *internal = &state->internal;
u8 lsb, msb;
- u32 i;
*ber = 0;
@@ -1143,14 +1142,9 @@
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 */
@@ -1163,13 +1157,9 @@
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))));
