iwlwifi: make sure device is reset when unloading driver

Add unconditional call to apm_ops.stop() to reset device to low power state
when unloading driver.  Some paths have existed to unload driver *without*
resetting device, therefore some errors have persisted through multiple
load/unload cycles, until the whole platform gets rebooted; this is an
attempt to remedy some of those situations.  Sorry, I can't seem to find
a bughost.org bug that specifically has these symptoms, but I had it happen
recently here.

Note that this will *not* fix situations in which the PCI express bus has
crashed (evidenced by register reads showing "0xffffffff"), e.g. bughost.org
1855 and 2096; device is unreachable from driver in those cases.

Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 18 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index ea1b9315f17c..fa1672e99e4b 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -3256,6 +3256,15 @@ static void __devexit iwl_pci_remove(struct pci_dev *pdev)
                 iwl_down(priv);
         }
 
+        /*
+         * Make sure device is reset to low power before unloading driver.
+         * This may be redundant with iwl_down(), but there are paths to
+         * run iwl_down() without calling apm_ops.stop(), and there are
+         * paths to avoid running iwl_down() at all before leaving driver.
+         * This (inexpensive) call *makes sure* device is reset.
+         */
+        priv->cfg->ops->lib->apm_ops.stop(priv);
+
         iwl_tt_exit(priv);
 
         /* make sure we flush any pending irq or
diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index 9a430eed34ad..bfd7f497157f 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -4135,6 +4135,15 @@ static void __devexit iwl3945_pci_remove(struct pci_dev *pdev)
                 iwl3945_down(priv);
         }
 
+        /*
+         * Make sure device is reset to low power before unloading driver.
+         * This may be redundant with iwl_down(), but there are paths to
+         * run iwl_down() without calling apm_ops.stop(), and there are
+         * paths to avoid running iwl_down() at all before leaving driver.
+         * This (inexpensive) call *makes sure* device is reset.
+         */
+        priv->cfg->ops->lib->apm_ops.stop(priv);
+
         /* make sure we flush any pending irq or
          * tasklet for the driver
          */