| From 72bfcee11cf89509795c56b0e40a3785ab00bbdd Mon Sep 17 00:00:00 2001 |
| From: Jarkko Nikula <jarkko.nikula@linux.intel.com> |
| Date: Tue, 30 Apr 2019 17:23:22 +0300 |
| Subject: i2c: Prevent runtime suspend of adapter when Host Notify is required |
| |
| 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; |
| } |
