tda1004x: only update the frontend properties if locked

commit e8beb02343e7582980c6705816cd957cf4f74c7a upstream.

The tda1004x was updating the properties cache before locking.
If the device is not locked, the data at the registers are just
random values with no real meaning.

This caused the driver to fail with libdvbv5, as such library
calls GET_PROPERTY from time to time, in order to return the
DVB stats.

Tested with a saa7134 card 78:
	ASUSTeK P7131 Dual, vendor PCI ID: 1043:4862

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/drivers/media/dvb/frontends/tda1004x.c b/drivers/media/dvb/frontends/tda1004x.c
index f2a8abe0a243b87b09d09df9098991ba23036562..97696c39a8b6071dccfa265ee946e5947b145e0c 100644 (file)
--- a/drivers/media/dvb/frontends/tda1004x.c
+++ b/drivers/media/dvb/frontends/tda1004x.c
@@ -898,9 +898,18 @@ static int tda1004x_set_fe(struct dvb_frontend* fe,
 static int tda1004x_get_fe(struct dvb_frontend* fe, struct dvb_frontend_parameters *fe_params)
 {
        struct tda1004x_state* state = fe->demodulator_priv;
+       int status;
 
        dprintk("%s\n", __func__);
 
+       status = tda1004x_read_byte(state, TDA1004X_STATUS_CD);
+       if (status == -1)
+               return -EIO;
+
+       /* Only update the properties cache if device is locked */
+       if (!(status & 8))
+               return 0;
+
        // inversion status
        fe_params->inversion = INVERSION_OFF;
        if (tda1004x_read_byte(state, TDA1004X_CONFC1) & 0x20)