Re: 5.11-rc device reordering breaks ThinkPad rmi4 suspend

On Mon, 11 Jan 2021, Rafael J. Wysocki wrote:

On Mon, Jan 11, 2021 at 5:44 AM Hugh Dickins [off-list ref] wrote:

quoted

Hi Rafael,

Synaptics RMI4 SMBus touchpad on ThinkPad X1 Carbon (5th generation)
fails to suspend when running 5.11-rc kernels: bisected to
5b6164d3465f ("driver core: Reorder devices on successful probe"),
and reverting that fixes it.  dmesg.xz attached, but go ahead and ask
me to switch on a debug option to extract further info if that may help.

Does the driver abort the suspend transition by returning an error or
does something else happen?

Both.  Thierry has pointed to the lines showing failed suspend transition;
and I forgot to mention that the touchpad is unresponsive from then on
(I might not have noticed the failed suspend without that).  But I don't
suppose that unresponsiveness is worth worrying about: things went wrong
in suspend, so it's not surprising if the driver does not recover well.

Thank you both for getting on to this so quickly - but don't worry about
getting my touchpad working: I'm glad to see you discussing the wider
issues of ordering that this has brought up.

Hugh