From: Jarkko Nikula jarkko.nikula@linux.intel.com
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 ferdasyn@rocketmail.com 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 jarkko.nikula@linux.intel.com Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Tested-by: Keijo Vaara ferdasyn@rocketmail.com Signed-off-by: Wolfram Sang wsa@the-dreams.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/i2c/i2c-core-base.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -327,6 +327,8 @@ static int i2c_device_probe(struct devic
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 devi 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; }