Re: 5.11-rc device reordering breaks ThinkPad rmi4 suspend

On Mon, Jan 11, 2021 at 4:44 PM Hugh Dickins [off-list ref] wrote:

On Mon, 11 Jan 2021, Saravana Kannan wrote:

quoted

On Mon, Jan 11, 2021 at 3:42 PM Hugh Dickins [off-list ref] wrote:

quoted

On Mon, 11 Jan 2021, Saravana Kannan wrote:

quoted

I happen to have an X1 Carbon (different gen though) lying around and
I poked at its /sys folders. None of the devices in the rmi4_smbus are
considered the grandchildren of the i2c device. I think the real
problem is rmi_register_transport_device() [1] not setting up the
parent for any of the new devices it's adding.

Hugh, can you try this patch?

Just tried, but no, this patch does not help; but I bet
you're along the right lines, and something as simple will do it.

Did you see this patch change the organization of devices under /sys/devices/?
The rmi* devices need to be under one of the i2c devices after this
patch. Is that not the case? Or is that the case, but you are still
seeing suspend/resume issues?

Now that I look, yes, that patch has moved the directory
/sys/devices/rmi4-00
to
/sys/devices/pci0000:00/0000:00:1f.4/i2c-6/6-002c/rmi4-00

What about child devices of rmi4-00? Does it still have the
rmi4-00.fn* devices as children? I'd think so, but just double
checking.

But I still see the same suspend issues despite that.

Can you please get new logs to see if the failure reasons are still
the same? I'd think this parent/child relationship would at least
avoid the "Failed to read irqs" errors that seem to be due to I2C
dependency.

-Saravana