* keywest bugfix
@ 2004-03-20 13:43 Samuel Rydh
0 siblings, 0 replies; only message in thread
From: Samuel Rydh @ 2004-03-20 13:43 UTC (permalink / raw)
To: linuxppc-dev; +Cc: benh
The following patch fixes a deadlock in I2C probing:
===== drivers/i2c/busses/i2c-keywest.c 1.12 vs edited =====
--- 1.12/drivers/i2c/busses/i2c-keywest.c Mon Mar 15 11:25:23 2004
+++ edited/drivers/i2c/busses/i2c-keywest.c Sat Mar 20 14:33:07 2004
@@ -608,6 +608,7 @@
}
#endif /* POLLED_MODE */
+ pmac_low_i2c_unlock(np);
dev_set_drvdata(dev, iface);
for (i=0; i<nchan; i++) {
@@ -645,7 +646,6 @@
printk(KERN_INFO "Found KeyWest i2c on \"%s\", %d channel%s, stepping: %d bits\n",
np->parent->name, nchan, nchan > 1 ? "s" : "", bsteps);
- pmac_low_i2c_unlock(np);
return 0;
}
Without this patch, the deadlock occurs in the following situation:
- keywest holds the pmac_low_i2c_lock while registering the i2c adapter.
- i2c_add_adapter() notifies registered drivers by calling
driver->attach_adapter().
- a driver might access the i2c bus from attach_adapter() which
deadlocks since all xfer routines take the lock.
/Samuel
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
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