Re: OOPS w83781d during rmmod (2.5.70-bk1[1234])

["Mark M. Hoffman" <mhoffman@lightlink.com>]

* Martin Schlemmer <azarah@gentoo.org> [2003-06-09 07:34:30 +0200]:
> 
> Anyhow, Only change I have made to the w83781d driver, is one line
> (just tell it to that if the chip id is 0x72, its also of type
> w83726HF), but now (2.5.70-bk1[123]) it segfaults for me on rmmod, where
> it did not with 2.5.68 kernels when I still had the other board.  I will
> attach a oops tomorrow or such when I get home.

I reproduced the segfault here.  It looks like i2c_del_driver() tries
to call w83781d_detach_client() more than once now, partly because of
the safe list fix in 2.5.70-bk11.  But that function should only be
called for the "primary" client, not the subclients.

The quick/ugly patch below fixes the symptom, but maybe not the disease.
There might be more fundamental brokenness in the whole subclient scheme.
I'll keep looking when I get the chance.

--- linux-2.5.70-bk14/drivers/i2c/chips/w83781d.c	2003-06-10 00:49:19.831210956 -0400
+++ linux-2.5.70/drivers/i2c/chips/w83781d.c	2003-06-10 00:53:35.041027614 -0400
@@ -1412,6 +1412,10 @@
 	struct w83781d_data *data = i2c_get_clientdata(client);
 	int err;
 
+	/* if this is a subclient, do nothing */
+	if (!data)
+		return 0;
+
 	/* release ISA region or I2C subclients first */
 	if (i2c_is_isa_client(client)) {
 		release_region(client->addr, W83781D_EXTENT);

Regards,

-- 
Mark M. Hoffman
mhoffman@lightlink.com