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Commit fdaaee6c authored by Klaus Schmidinger's avatar Klaus Schmidinger Committed by Mauro Carvalho Chehab
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[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: default avatarKlaus Schmidinger <Klaus.Schmidinger@tvdr.de>
Cc: Manu Abraham <abraham.manu@gmail.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 4a628170

drivers/media/dvb/frontends/stb0899_drv.c

+6 −16
Original line number Diff line number Diff line
@@ -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;

			*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);

			}

			*ber = MAKEWORD16(msb, lsb);

			/* ber = ber * 10 ^ 7	*/

			*ber *= 10000000;

			*ber /= (-1 + (1 << (4 + 2 * STB0899_GETFIELD(NOE, internal->err_ctrl))));