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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/media/dvb-frontends/tda1004x.c b/drivers/media/dvb-frontends/tda1004x.c
index 0e209b56c76c1c487007121e336e0438944acb93..c6abeb4fba9db51827fc815fde920b1a30faa1fa 100644 (file)
--- a/drivers/media/dvb-frontends/tda1004x.c
+++ b/drivers/media/dvb-frontends/tda1004x.c
@@ -903,9 +903,18 @@ static int tda1004x_get_fe(struct dvb_frontend *fe)
 {
        struct dtv_frontend_properties *fe_params = &fe->dtv_property_cache;
        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)