From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Brunner , Guenter Roeck , Lee Jones Subject: [PATCH 3.14 049/158] mfd: kempld-core: Fix potential hang-up during boot Date: Sun, 4 May 2014 11:39:18 -0400 Message-Id: <20140504154036.653789527@linuxfoundation.org> In-Reply-To: <20140504154029.975081050@linuxfoundation.org> References: <20140504154029.975081050@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guenter Roeck commit 204747c970c0d568721c76ab8a57dde0e5dcf0d5 upstream. On PXT and COMe-cPC2 boards it is observed that the hardware mutex is acquired but not being released during initialization. This can result in a hang-up during boot if the driver is built into the kernel. Releasing the mutex twice if it was acquired fixes the problem. Subsequent request/release cycles work as expected, so the fix is only needed during initialization. Reviewed-by: Michael Brunner Tested-by: Michael Brunner Signed-off-by: Guenter Roeck Signed-off-by: Lee Jones Signed-off-by: Greg Kroah-Hartman --- drivers/mfd/kempld-core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/mfd/kempld-core.c +++ b/drivers/mfd/kempld-core.c @@ -322,9 +322,12 @@ static int kempld_detect_device(struct k return -ENODEV; } - /* Release hardware mutex if aquired */ - if (!(index_reg & KEMPLD_MUTEX_KEY)) + /* Release hardware mutex if acquired */ + if (!(index_reg & KEMPLD_MUTEX_KEY)) { iowrite8(KEMPLD_MUTEX_KEY, pld->io_index); + /* PXT and COMe-cPC2 boards may require a second release */ + iowrite8(KEMPLD_MUTEX_KEY, pld->io_index); + } mutex_unlock(&pld->lock);