Patch "Revert "Input: synaptics - Lenovo Thinkpad T460p devices should use RMI"" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

Revert "Input: synaptics - Lenovo Thinkpad T460p devices should use RMI"

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
revert-input-synaptics-lenovo-thinkpad-t460p-devices-should-use-rmi.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Arkadiusz Hiler <[email protected]>
Date: Wed, 7 Mar 2018 15:40:28 -0800
Subject: Revert "Input: synaptics - Lenovo Thinkpad T460p devices should use RMI"
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From: Arkadiusz Hiler <[email protected]>

commit 5444a992b4a73aa5246a432c482b20b89bce93a5 upstream.

This reverts commit 48282969826b3d3c76e908182f69724d86d995fe which caused the following issues:

1. On T460p with BIOS version 2.22 touchpad and trackpoint stop working after suspend-resume cycle. Due to strange state of the device another suspend is impossible.

The following dmesg errors can be observed:
thinkpad_acpi: EC reports that Thermal Table has changed
rmi4_smbus 7-002c: failed to get SMBus version number!
rmi4_physical rmi4-00: rmi_driver_reset_handler: Failed to read current IRQ mask. rmi4_f01 rmi4-00.fn01: Failed to restore normal operation: -16.
rmi4_f01 rmi4-00.fn01: Resume failed with code -16.
rmi4_physical rmi4-00: Failed to suspend functions: -16
rmi4_smbus 7-002c: Failed to resume device: -16
PM: resume devices took 0.640 seconds
rmi4_f03 rmi4-00.fn03: rmi_f03_pt_write: Failed to write to F03 TX register (-16). rmi4_physical rmi4-00: rmi_driver_clear_irq_bits: Failed to change enabled interrupts! rmi4_physical rmi4-00: rmi_driver_set_irq_bits: Failed to change enabled interrupts!
psmouse: probe of serio3 failed with error -1

2. On another T460p with BIOS version 2.15 two finger scrolling gesture on the touchpad stops working after suspend-resume cycle (about 75% reproducibility, when it still works, the scrolling gesture becomes laggy). Nothing suspicious appears in the dmesg.

Analysis form Richard Schütz:

"RMI is unreliable on the ThinkPad T460p because the device is affected by the firmware behavior addressed in a7ae81952cda ("i2c: i801: Allow ACPI SystemIO OpRegion to conflict with PCI BAR")."

The affected devices often show:

i801_smbus 0000:00:1f.4: BIOS is accessing SMBus registers i801_smbus 0000:00:1f.4: Driver SMBus register access inhibited

---
 drivers/input/mouse/synaptics.c |    1 -
 1 file changed, 1 deletion(-)

@@ -173,7 +173,6 @@ static const char * const smbus_pnp_ids[
 	"LEN0046", /* X250 */
 	"LEN004a", /* W541 */
 	"LEN200f", /* T450s */
-	"LEN2018", /* T460p */
 	NULL
 };
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/revert-input-synaptics-lenovo-thinkpad-t460p-devices-should-use-rmi.patch