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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Evan Green <evgreen@chromium.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 113/171] Input: atmel_mxt_ts - disable IRQ across suspend
Date:   Thu,  2 Jan 2020 23:07:24 +0100
Message-Id: <20200102220602.820154792@linuxfoundation.org>
In-Reply-To: <20200102220546.960200039@linuxfoundation.org>
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From: Evan Green <evgreen@chromium.org>

[ Upstream commit 463fa44eec2fef50d111ed0199cf593235065c04 ]

Across suspend and resume, we are seeing error messages like the following:

atmel_mxt_ts i2c-PRP0001:00: __mxt_read_reg: i2c transfer failed (-121)
atmel_mxt_ts i2c-PRP0001:00: Failed to read T44 and T5 (-121)

This occurs because the driver leaves its IRQ enabled. Upon resume, there
is an IRQ pending, but the interrupt is serviced before both the driver and
the underlying I2C bus have been resumed. This causes EREMOTEIO errors.

Disable the IRQ in suspend, and re-enable it on resume. If there are cases
where the driver enters suspend with interrupts disabled, that's a bug we
should fix separately.

Signed-off-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index c2fb0236a47c..8d871fcb7912 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -3206,6 +3206,8 @@ static int __maybe_unused mxt_suspend(struct device *dev)
 
 	mutex_unlock(&input_dev->mutex);
 
+	disable_irq(data->irq);
+
 	return 0;
 }
 
@@ -3218,6 +3220,8 @@ static int __maybe_unused mxt_resume(struct device *dev)
 	if (!input_dev)
 		return 0;
 
+	enable_irq(data->irq);
+
 	mutex_lock(&input_dev->mutex);
 
 	if (input_dev->users)
-- 
2.20.1