From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH] Input: i8042 - i8042_flush fix for a full 8042 buffer Date: Wed, 18 Sep 2013 07:44:22 -0700 Message-ID: <20130918144420.GB16424@core.coreip.homeip.net> References: <52399E2C.7000805@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <52399E2C.7000805@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Andrey Moiseev Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-input@vger.kernel.org Hi Andrey, On Wed, Sep 18, 2013 at 04:35:56PM +0400, Andrey Moiseev wrote: > When 8042 internal data buffer is full, the driver > erroneously decides that the controller is not present. > > I've already sent this 2 weeks ago, but that message received no comments. > Sorry about the delay. How about we rework it a bit and make flush return success/error instead of number of bytes read, like in the patch below? Thanks. -- Dmitry Input: i8042 - i8042_flush fix for a full 8042 buffer From: Andrey Moiseev When 8042 internal data buffer is full, the driver erroneously decides that the controller is not present. i8042_flush returns the number of flushed bytes, which is in 0 - I8042_BUFFER_SIZE range inclusive. Therefore, i8042_flush has no way to indicate an error. Moreover i8042_controller_check takes initially full buffer (i8042_flush returned I8042_BUFFER_SIZE) as a sign of absence of the controller. Let's change i8042 to return success/error instead and make sure we do not return error prematurely. Signed-off-by: Andrey Moiseev Signed-off-by: Dmitry Torokhov --- drivers/input/serio/i8042.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/drivers/input/serio/i8042.c b/drivers/input/serio/i8042.c index 78e4de4..52c9ebf 100644 --- a/drivers/input/serio/i8042.c +++ b/drivers/input/serio/i8042.c @@ -223,21 +223,26 @@ static int i8042_flush(void) { unsigned long flags; unsigned char data, str; - int i = 0; + int count = 0; + int retval = 0; spin_lock_irqsave(&i8042_lock, flags); - while (((str = i8042_read_status()) & I8042_STR_OBF) && (i < I8042_BUFFER_SIZE)) { - udelay(50); - data = i8042_read_data(); - i++; - dbg("%02x <- i8042 (flush, %s)\n", - data, str & I8042_STR_AUXDATA ? "aux" : "kbd"); + while ((str = i8042_read_status()) & I8042_STR_OBF) { + if (count++ < I8042_BUFFER_SIZE) { + udelay(50); + data = i8042_read_data(); + dbg("%02x <- i8042 (flush, %s)\n", + data, str & I8042_STR_AUXDATA ? "aux" : "kbd"); + } else { + retval = -EIO; + break; + } } spin_unlock_irqrestore(&i8042_lock, flags); - return i; + return retval; } /* @@ -849,7 +854,7 @@ static int __init i8042_check_aux(void) static int i8042_controller_check(void) { - if (i8042_flush() == I8042_BUFFER_SIZE) { + if (i8042_flush()) { pr_err("No controller found\n"); return -ENODEV; }