Re: [PATCH] Latest version of em28xx / em28xx-dvb patch for PCTV 290e

[Chris Rankin <rankincj@yahoo.com>]

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Next patch: By default, the DVB framework tries to put a frontend to sleep after 
it has been shut down. This obviously doesn't work for a USB device that has 
been disconnected, and can result in occasional errors in dmesg about I2C writes 
failing with error code -19.

The patch works by nulling out the function pointers that the DVB framework 
would otherwise try to call. I have therefore declared the structs in the 
tda18271 and cxd2820r modules to be "const", so that we know that they are 
supposed only to be templates.

Signed-off-by: Chris Rankin <rankincj@yahoo.com>


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--- linux-3.0/drivers/media/common/tuners/tda18271-fe.c.orig	2011-08-18 16:55:53.000000000 +0100
+++ linux-3.0/drivers/media/common/tuners/tda18271-fe.c	2011-08-18 23:12:55.000000000 +0100
@@ -1230,7 +1230,7 @@
 	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,
--- linux-3.0/drivers/media/dvb/frontends/cxd2820r_core.c.orig	2011-08-18 16:56:02.000000000 +0100
+++ linux-3.0/drivers/media/dvb/frontends/cxd2820r_core.c	2011-08-18 23:14:06.000000000 +0100
@@ -778,7 +778,7 @@
 }
 EXPORT_SYMBOL(cxd2820r_get_tuner_i2c_adapter);
 
-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)
@@ -844,7 +844,7 @@
 }
 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 = {
--- linux-3.0/drivers/media/video/em28xx/em28xx-dvb.c.orig	2011-08-17 08:52:30.000000000 +0100
+++ linux-3.0/drivers/media/video/em28xx/em28xx-dvb.c	2011-08-18 23:17:42.000000000 +0100
@@ -720,6 +720,12 @@
 	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 dvb_fini(struct em28xx *dev)
 {
 	if (!dev->board.has_dvb) {
@@ -728,8 +734,17 @@
 	}
 
 	if (dev->dvb) {
-		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. */
+			prevent_sleep(&dvb->fe[0]->ops);
+			prevent_sleep(&dvb->fe[1]->ops);
+		}
+
+		unregister_dvb(dvb);
+		kfree(dvb);
 		dev->dvb = NULL;
 	}