Patch "mei: txe: don't clean an unprocessed interrupt cause." has been added to the 4.4-stable tree

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

mei: txe: don't clean an unprocessed interrupt cause.

to the 4.4-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:
mei-txe-don-t-clean-an-unprocessed-interrupt-cause.patch
and it can be found in the queue-4.4 subdirectory.

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

From: Alexander Usyskin <[email protected]>
Date: Wed, 19 Oct 2016 01:34:48 +0300
Subject: mei: txe: don't clean an unprocessed interrupt cause.

From: Alexander Usyskin <[email protected]>

commit 43605e293eb13c07acb546c14f407a271837af17 upstream.

SEC registers are not accessible when the TXE device is in low power state, hence the SEC interrupt cannot be processed if device is not awake.

In some rare cases entrance to low power state (aliveness off) and input ready bits can be signaled at the same time, resulting in communication stall as input ready won't be signaled again after waking up. To resolve this IPC_HHIER_SEC bit in HHISR_REG should not be cleaned if the interrupt is not processed.

---
 drivers/misc/mei/hw-txe.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -972,11 +972,13 @@ static bool mei_txe_check_and_ack_intrs(
 	hisr = mei_txe_br_reg_read(hw, HISR_REG);
 
 	aliveness = mei_txe_aliveness_get(dev);
-	if (hhisr & IPC_HHIER_SEC && aliveness)
+	if (hhisr & IPC_HHIER_SEC && aliveness) {
 		ipc_isr = mei_txe_sec_reg_read_silent(hw,
 				SEC_IPC_HOST_INT_STATUS_REG);
-	else
+	} else {
 		ipc_isr = 0;
+		hhisr &= ~IPC_HHIER_SEC;
+	}
 
 	generated = generated ||
 		(hisr & HISR_INT_STS_MSK) ||

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

queue-4.4/mei-txe-don-t-clean-an-unprocessed-interrupt-cause.patch