Patch "i2c: core: Restore acpi_walk_dep_device_list() getting called after registering the ACPI i2c devs" has been added to the 5.8-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    i2c: core: Restore acpi_walk_dep_device_list() getting called after registering the ACPI i2c devs

to the 5.8-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:
     i2c-core-restore-acpi_walk_dep_device_list-getting-c.patch
and it can be found in the queue-5.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e900ed08ccc9816c0f9912ea6b82c7e0807820a6
Author: Hans de Goede <hdegoede@xxxxxxxxxx>
Date:   Wed Oct 14 16:41:58 2020 +0200

    i2c: core: Restore acpi_walk_dep_device_list() getting called after registering the ACPI i2c devs
    
    [ Upstream commit 8058d69905058ec8f467a120b5ec5bb831ea67f3 ]
    
    Commit 21653a4181ff ("i2c: core: Call i2c_acpi_install_space_handler()
    before i2c_acpi_register_devices()")'s intention was to only move the
    acpi_install_address_space_handler() call to the point before where
    the ACPI declared i2c-children of the adapter where instantiated by
    i2c_acpi_register_devices().
    
    But i2c_acpi_install_space_handler() had a call to
    acpi_walk_dep_device_list() hidden (that is I missed it) at the end
    of it, so as an unwanted side-effect now acpi_walk_dep_device_list()
    was also being called before i2c_acpi_register_devices().
    
    Move the acpi_walk_dep_device_list() call to the end of
    i2c_acpi_register_devices(), so that it is once again called *after*
    the i2c_client-s hanging of the adapter have been created.
    
    This fixes the Microsoft Surface Go 2 hanging at boot.
    
    Fixes: 21653a4181ff ("i2c: core: Call i2c_acpi_install_space_handler() before i2c_acpi_register_devices()")
    Link: https://bugzilla.kernel.org/show_bug.cgi?id=209627
    Reported-by: Rainer Finke <rainer@xxxxxxxx>
    Reported-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx>
    Suggested-by: Maximilian Luz <luzmaximilian@xxxxxxxxx>
    Tested-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx>
    Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
    Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/i2c/i2c-core-acpi.c b/drivers/i2c/i2c-core-acpi.c
index 2ade99b105b91..bbf8dd491d245 100644
--- a/drivers/i2c/i2c-core-acpi.c
+++ b/drivers/i2c/i2c-core-acpi.c
@@ -264,6 +264,7 @@ static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
 void i2c_acpi_register_devices(struct i2c_adapter *adap)
 {
 	acpi_status status;
+	acpi_handle handle;
 
 	if (!has_acpi_companion(&adap->dev))
 		return;
@@ -274,6 +275,15 @@ void i2c_acpi_register_devices(struct i2c_adapter *adap)
 				     adap, NULL);
 	if (ACPI_FAILURE(status))
 		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
+
+	if (!adap->dev.parent)
+		return;
+
+	handle = ACPI_HANDLE(adap->dev.parent);
+	if (!handle)
+		return;
+
+	acpi_walk_dep_device_list(handle);
 }
 
 const struct acpi_device_id *
@@ -729,7 +739,6 @@ int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
 		return -ENOMEM;
 	}
 
-	acpi_walk_dep_device_list(handle);
 	return 0;
 }