Patch "iwlwifi: pcie: fix prepare card flow" has been added to the 4.1-stable tree

Patch "iwlwifi: pcie: fix prepare card flow" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    iwlwifi: pcie: fix prepare card flow

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iwlwifi-pcie-fix-prepare-card-flow.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c9fdec9f3970eeaa1b176422f46167f5f5158804 Mon Sep 17 00:00:00 2001
From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Date: Mon, 20 Jul 2015 12:14:39 +0300
Subject: iwlwifi: pcie: fix prepare card flow

From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

commit c9fdec9f3970eeaa1b176422f46167f5f5158804 upstream.

When the card is not owned by the PCIe bus, we need to
acquire ownership first. This flow is implemented in
iwl_pcie_prepare_card_hw. Because of a hardware bug, we
need to disable link power management before we can
request ownership otherwise the other user of the device
won't get notified that we are requesting the device which
will prevent us from acquire ownership.

Same holds for the down flow where we need to make sure
that any other potential user is notified that the driver
is going down.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/iwlwifi/pcie/trans.c |   22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/iwlwifi/pcie/trans.c
@@ -457,10 +457,16 @@ static void iwl_pcie_apm_stop(struct iwl
 		if (trans->cfg->device_family == IWL_DEVICE_FAMILY_7000)
 			iwl_set_bits_prph(trans, APMG_PCIDEV_STT_REG,
 					  APMG_PCIDEV_STT_VAL_WAKE_ME);
-		else if (trans->cfg->device_family == IWL_DEVICE_FAMILY_8000)
+		else if (trans->cfg->device_family == IWL_DEVICE_FAMILY_8000) {
+			iwl_set_bit(trans, CSR_DBG_LINK_PWR_MGMT_REG,
+				    CSR_RESET_LINK_PWR_MGMT_DISABLED);
 			iwl_set_bit(trans, CSR_HW_IF_CONFIG_REG,
 				    CSR_HW_IF_CONFIG_REG_PREPARE |
 				    CSR_HW_IF_CONFIG_REG_ENABLE_PME);
+			mdelay(1);
+			iwl_clear_bit(trans, CSR_DBG_LINK_PWR_MGMT_REG,
+				      CSR_RESET_LINK_PWR_MGMT_DISABLED);
+		}
 		mdelay(5);
 	}
 
@@ -555,6 +561,10 @@ static int iwl_pcie_prepare_card_hw(stru
 	if (ret >= 0)
 		return 0;
 
+	iwl_set_bit(trans, CSR_DBG_LINK_PWR_MGMT_REG,
+		    CSR_RESET_LINK_PWR_MGMT_DISABLED);
+	msleep(1);
+
 	for (iter = 0; iter < 10; iter++) {
 		/* If HW is not ready, prepare the conditions to check again */
 		iwl_set_bit(trans, CSR_HW_IF_CONFIG_REG,
@@ -562,8 +572,10 @@ static int iwl_pcie_prepare_card_hw(stru
 
 		do {
 			ret = iwl_pcie_set_hw_ready(trans);
-			if (ret >= 0)
-				return 0;
+			if (ret >= 0) {
+				ret = 0;
+				goto out;
+			}
 
 			usleep_range(200, 1000);
 			t += 200;
@@ -573,6 +585,10 @@ static int iwl_pcie_prepare_card_hw(stru
 
 	IWL_ERR(trans, "Couldn't prepare the card\n");
 
+out:
+	iwl_clear_bit(trans, CSR_DBG_LINK_PWR_MGMT_REG,
+		      CSR_RESET_LINK_PWR_MGMT_DISABLED);
+
 	return ret;
 }
 


Patches currently in stable-queue which might be from emmanuel.grumbach@intel.com are

queue-4.1/iwlwifi-pcie-fix-prepare-card-flow.patch