[media] em28xx: don't sleep on disconnect

The DVB framework will try to power-down an adapter that no-one is using
any more, but this assumes that the adapter is still connected to the
machine. That's not always true for a USB adapter, so disable the sleep
operations when the adapter has been physically unplugged.

This prevents I2C write failures with error -19 from appearing
occasionally in the dmesg log.

Signed-off-by: Chris Rankin <rankincj@yahoo.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 23 insertions, 5 deletions

diff --git a/drivers/media/common/tuners/tda18271-fe.c b/drivers/media/common/tuners/tda18271-fe.c
index 57022e88e338..63cc4004e211 100644
--- a/drivers/media/common/tuners/tda18271-fe.c
+++ b/drivers/media/common/tuners/tda18271-fe.c
@@ -1230,7 +1230,7 @@ static int tda18271_set_config(struct dvb_frontend *fe, void *priv_cfg)
         return 0;
 }
 
-static struct dvb_tuner_ops tda18271_tuner_ops = {
+static const struct dvb_tuner_ops tda18271_tuner_ops = {
         .info = {
                 .name = "NXP TDA18271HD",
                 .frequency_min  =  45000000,
diff --git a/drivers/media/dvb/frontends/cxd2820r_core.c b/drivers/media/dvb/frontends/cxd2820r_core.c
index 01512670c6a6..036480f967b7 100644
--- a/drivers/media/dvb/frontends/cxd2820r_core.c
+++ b/drivers/media/dvb/frontends/cxd2820r_core.c
@@ -742,7 +742,7 @@ static int cxd2820r_i2c_gate_ctrl(struct dvb_frontend *fe, int enable)
         return cxd2820r_wr_reg_mask(priv, 0xdb, enable ? 1 : 0, 0x1);
 }
 
-static struct dvb_frontend_ops cxd2820r_ops[2];
+static const struct dvb_frontend_ops cxd2820r_ops[2];
 
 struct dvb_frontend *cxd2820r_attach(const struct cxd2820r_config *cfg,
         struct i2c_adapter *i2c, struct dvb_frontend *fe)
@@ -796,7 +796,7 @@ error:
 }
 EXPORT_SYMBOL(cxd2820r_attach);
 
-static struct dvb_frontend_ops cxd2820r_ops[2] = {
+static const struct dvb_frontend_ops cxd2820r_ops[2] = {
         {
                 /* DVB-T/T2 */
                 .info = {
diff --git a/drivers/media/video/em28xx/em28xx-dvb.c b/drivers/media/video/em28xx/em28xx-dvb.c
index b606fc7f842d..62b558ddc02e 100644
--- a/drivers/media/video/em28xx/em28xx-dvb.c
+++ b/drivers/media/video/em28xx/em28xx-dvb.c
@@ -842,6 +842,13 @@ out_free:
         goto ret;
 }
 
+static inline void prevent_sleep(struct dvb_frontend_ops *ops)
+{
+        ops->set_voltage = NULL;
+        ops->sleep = NULL;
+        ops->tuner_ops.sleep = NULL;
+}
+
 static int em28xx_dvb_fini(struct em28xx *dev)
 {
         if (!dev->board.has_dvb) {
@@ -850,8 +857,19 @@ static int em28xx_dvb_fini(struct em28xx *dev)
         }
 
         if (dev->dvb) {
-                em28xx_unregister_dvb(dev->dvb);
-                kfree(dev->dvb);
+                struct em28xx_dvb *dvb = dev->dvb;
+
+                if (dev->state & DEV_DISCONNECTED) {
+                        /* We cannot tell the device to sleep
+                         * once it has been unplugged. */
+                        if (dvb->fe[0])
+                                prevent_sleep(&dvb->fe[0]->ops);
+                        if (dvb->fe[1])
+                                prevent_sleep(&dvb->fe[1]->ops);
+                }
+
+                em28xx_unregister_dvb(dvb);
+                kfree(dvb);
                 dev->dvb = NULL;
         }