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Patch "iwlwifi: pcie: enable interrupts before releasing the NIC's CPU" has been added to the 4.7-stable tree

PATCH [email protected] 1 participant 1 message Aug 18, 2016

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

iwlwifi: pcie: enable interrupts before releasing the NIC's CPU

to the 4.7-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-enable-interrupts-before-releasing-the-nic-s-cpu.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 2aabdbdc17b7c53490337bfc58de3409c84d85d2 Mon Sep 17 00:00:00 2001

From: Emmanuel Grumbach <[email protected]>
Date: Wed, 8 Jun 2016 23:07:31 +0300
Subject: iwlwifi: pcie: enable interrupts before releasing the NIC's CPU

From: Emmanuel Grumbach <[email protected]>

commit 2aabdbdc17b7c53490337bfc58de3409c84d85d2 upstream.

The NIC's CPU gets started after the firmware has been written to its memory. The first thing it does is to send an interrupt to let the driver know that it is running. In order to get that interrupt, the driver needs to make sure it is not masked. Of course, the interrupt needs to be enabled in the driver before the CPU starts to run.
I mistakenly inversed those two steps leading to races which prevented the driver from getting the alive interrupt from the firmware.
Fix that.

Fixes a6bd005fe92 ("iwlwifi: pcie: fix RF-Kill vs. firmware load race")
---
 drivers/net/wireless/intel/iwlwifi/pcie/trans.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
drivers/net/wireless/intel/iwlwifi/pcie/trans.c +4 -1
@@ -801,6 +801,8 @@ static int iwl_pcie_load_cpu_sections_80
 
 	*first_ucode_section = last_read_idx;
 
+	iwl_enable_interrupts(trans);
+
 	if (cpu == 1)
 		iwl_write_direct32(trans, FH_UCODE_LOAD_STATUS, 0xFFFF);
 	else
@@ -980,6 +982,8 @@ static int iwl_pcie_load_given_ucode(str
 		iwl_pcie_apply_destination(trans);
 	}
 
+	iwl_enable_interrupts(trans);
+
 	/* release CPU reset */
 	iwl_write32(trans, CSR_RESET, 0);
 
@@ -1215,7 +1219,6 @@ static int iwl_trans_pcie_start_fw(struc
 		ret = iwl_pcie_load_given_ucode_8000(trans, fw);
 	else
 		ret = iwl_pcie_load_given_ucode(trans, fw);
-	iwl_enable_interrupts(trans);
 
 	/* re-check RF-Kill state since we may have missed the interrupt */
 	hw_rfkill = iwl_is_rfkill_set(trans);

Patches currently in stable-queue which might be from [email protected] are

queue-4.7/iwlwifi-pcie-enable-interrupts-before-releasing-the-nic-s-cpu.patch queue-4.7/iwlwifi-pcie-fix-a-race-in-firmware-loading-flow.patch