On Wed, Nov 25, 2020 at 10:10:22PM +0800, Coiby Xu wrote:
For a broken touchpad, it may take several months or longer to be fixed. Polling mode could be a fallback solution for enthusiastic Linux users when they have a new laptop. It also acts like a debugging feature. If polling mode works for a broken touchpad, we can almost be certain the root cause is related to the interrupt or power setting.
This patch could fix touchpads of Lenovo AMD gaming laptops including Legion-5 15ARH05 (R7000), Legion-5P (R7000P) and IdeaPad Gaming 3 15ARH05.
When polling mode is enabled, an I2C device can't wake up the suspended system since enable/disable_irq_wake is invalid for polling mode.
Three module parameters are added to i2c-hid, - polling_mode: by default set to 0, i.e., polling is disabled - polling_interval_idle_ms: the polling internal when the touchpad is idle, default to 10ms - polling_interval_active_us: the polling internal when the touchpad is active, default to 4000us
User can change the last two runtime polling parameter by writing to /sys/module/i2c_hid/parameters/polling_interval_{idle_ms,active_us}.
Note xf86-input-synaptics doesn't work well with this polling mode for the Synaptics touchpad. The Synaptics touchpad would often locks into scroll mode when using multitouch gestures [1]. One remedy is to decrease the polling interval.
Thanks to Barnabás's thorough review of this patch and the useful feedback!
[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1887190/comments/235
Cc: stable@vger.kernel.org Cc: Barnabás Pőcze pobrn@protonmail.com BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1887190 Signed-off-by: Coiby Xu coiby.xu@gmail.com
drivers/hid/i2c-hid/i2c-hid-core.c | 152 +++++++++++++++++++++++++++-- 1 file changed, 142 insertions(+), 10 deletions(-)
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c index aeff1ffb0c8b..f25503f31ccf 100644 --- a/drivers/hid/i2c-hid/i2c-hid-core.c +++ b/drivers/hid/i2c-hid/i2c-hid-core.c @@ -36,6 +36,8 @@ #include <linux/hid.h> #include <linux/mutex.h> #include <linux/acpi.h> +#include <linux/kthread.h> +#include <linux/gpio/driver.h> #include <linux/of.h> #include <linux/regulator/consumer.h> @@ -60,6 +62,25 @@ #define I2C_HID_PWR_ON 0x00 #define I2C_HID_PWR_SLEEP 0x01 +/* polling mode */ +#define I2C_HID_POLLING_DISABLED 0 +#define I2C_HID_POLLING_GPIO_PIN 1 +#define I2C_HID_POLLING_INTERVAL_ACTIVE_US 4000 +#define I2C_HID_POLLING_INTERVAL_IDLE_MS 10
+static u8 polling_mode; +module_param(polling_mode, byte, 0444); +MODULE_PARM_DESC(polling_mode, "How to poll (default=0) - 0 disabled; 1 based on GPIO pin's status");
Module parameters are for the 1990's, they are global and horrible to try to work with. You should provide something on a per-device basis, as what happens if your system requires different things here for different devices? You set this for all devices :(
thanks,
greg k-h