[C/D/Unstable] [PATCH] HID: i2c-hid: Disable runtime PM for LG touchscreen

[Kai-Heng Feng]

BugLink: https://bugs.launchpad.net/bugs/1805085

LG touchscreen (1fd2:8001) stops working after reboot:
[ 4.859153] i2c_hid i2c-SAPS2101:00: i2c_hid_get_input: incomplete report (64/66)
[ 4.936070] i2c_hid i2c-SAPS2101:00: i2c_hid_get_input: incomplete report (64/66)
[ 9.948224] i2c_hid i2c-SAPS2101:00: failed to reset device.

The device in question stops working after receives SLEEP, ON, SLEEP
commands in a short period. The scenario is like this:
- Once the desktop session closes, it also closed the hid device, so the
device gets runtime suspended and receives a SLEEP command.
- Before calling shutdown callback, it gets runtime resumed and received
an ON command.
- In the shutdown callback, it receives another SLEEP command.

I failed to find a reliable interval between ON/SLEEP commands that can
make it work, so let's simply disable runtime PM for the device.

Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
Signed-off-by: Jiri Kosina <jkosina at suse.cz>
(backported from commit 86c31524b27c7e686841dd4a79eda95cfd989f16)
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
---
 drivers/hid/hid-ids.h         | 1 +
 drivers/hid/i2c-hid/i2c-hid.c | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 9590394b55fc..f32be708b324 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -701,6 +701,7 @@
 #define USB_VENDOR_ID_LG		0x1fd2
 #define USB_DEVICE_ID_LG_MULTITOUCH	0x0064
 #define USB_DEVICE_ID_LG_MELFAS_MT	0x6007
+#define I2C_DEVICE_ID_LG_8001		0x8001
 
 #define USB_VENDOR_ID_LOGITECH		0x046d
 #define USB_DEVICE_ID_LOGITECH_AUDIOHUB 0x0a0e
diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index d17cf6e323b2..0babeae0f2a0 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -171,6 +171,8 @@ static const struct i2c_hid_quirks {
 	{ I2C_VENDOR_ID_HANTICK, I2C_PRODUCT_ID_HANTICK_5288,
 		I2C_HID_QUIRK_NO_IRQ_AFTER_RESET |
 		I2C_HID_QUIRK_NO_RUNTIME_PM },
+	{ USB_VENDOR_ID_LG, I2C_DEVICE_ID_LG_8001,
+		I2C_HID_QUIRK_NO_RUNTIME_PM },
 	{ 0, 0 }
 };
 
-- 
2.17.1