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

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.

Cc: stable@vger.kernel.org
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mei/hw-txe.c b/drivers/misc/mei/hw-txe.c
index e6e5e55a12ed45f09577899198e7a8735ae7a0e8..60415a2bfcbd4c3f67a832bf3bc388b0af9a1270 100644 (file)
--- a/drivers/misc/mei/hw-txe.c
+++ b/drivers/misc/mei/hw-txe.c
@@ -981,11 +981,13 @@ static bool mei_txe_check_and_ack_intrs(struct mei_device *dev, bool do_ack)
        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) ||