From b19c230648b57b12b754e85750c8d665a906dbb4 Mon Sep 17 00:00:00 2001 From: Jarkko Nikula Date: Tue, 30 Apr 2019 17:23:22 +0300 Subject: [PATCH] i2c: Prevent runtime suspend of adapter when Host Notify is required commit 72bfcee11cf89509795c56b0e40a3785ab00bbdd upstream. Multiple users have reported their Synaptics touchpad has stopped working between v4.20.1 and v4.20.2 when using SMBus interface. The culprit for this appeared to be commit c5eb1190074c ("PCI / PM: Allow runtime PM without callback functions") that fixed the runtime PM for i2c-i801 SMBus adapter. Those Synaptics touchpad are using i2c-i801 for SMBus communication and testing showed they are able to get back working by preventing the runtime suspend of adapter. Normally when i2c-i801 SMBus adapter transmits with the client it resumes before operation and autosuspends after. However, if client requires SMBus Host Notify protocol, what those Synaptics touchpads do, then the host adapter must not go to runtime suspend since then it cannot process incoming SMBus Host Notify commands the client may send. Fix this by keeping I2C/SMBus adapter active in case client requires Host Notify. Reported-by: Keijo Vaara Link: https://bugzilla.kernel.org/show_bug.cgi?id=203297 Fixes: c5eb1190074c ("PCI / PM: Allow runtime PM without callback functions") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Jarkko Nikula Acked-by: Rafael J. Wysocki Tested-by: Keijo Vaara Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/i2c-core-base.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index 6dd74cc35c84..5b0e1d9e5adc 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -327,6 +327,8 @@ static int i2c_device_probe(struct device *dev) if (client->flags & I2C_CLIENT_HOST_NOTIFY) { dev_dbg(dev, "Using Host Notify IRQ\n"); + /* Keep adapter active when Host Notify is required */ + pm_runtime_get_sync(&client->adapter->dev); irq = i2c_smbus_host_notify_to_irq(client); } else if (dev->of_node) { irq = of_irq_get_byname(dev->of_node, "irq"); @@ -431,6 +433,8 @@ static int i2c_device_remove(struct device *dev) device_init_wakeup(&client->dev, false); client->irq = client->init_irq; + if (client->flags & I2C_CLIENT_HOST_NOTIFY) + pm_runtime_put(&client->adapter->dev); return status; } -- 2.11.0