Input: psmouse - fix fast_reconnect function for PS/2 mode

commit e2cb5cc8 upstream.

When the SMBus connection is attempted psmouse_smbus_init() sets
the fast_reconnect pointer to psmouse_smbus_reconnecti(). If SMBus
initialization fails, elantech_setup_ps2() and synaptics_init_ps2() will
fallback to PS/2 mode, replacing the psmouse private data. This can cause
issues on resume, since psmouse_smbus_reconnect() expects to find an
instance of struct psmouse_smbus_dev in psmouse->private.

The issue was uncovered when in 92e24e0e ("Input: psmouse - add
delay when deactivating for SMBus mode") psmouse_smbus_reconnect()
started attempting to use more of the data structure. The commit was
since reverted, not because it was at fault, but because there was found
a better way of doing what it was attempting to do.

Fix the problem by resetting the fast_reconnect pointer in psmouse
structure in elantech_setup_ps2() and synaptics_init_ps2() when the PS/2
mode is used.

Reported-by: Thorsten Leemhuis <linux@leemhuis.info>
Tested-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jeffery Miller <jefferymiller@google.com>
Fixes: bf232e46 ("Input: psmouse-smbus - allow to control psmouse_deactivate")
Link: https://lore.kernel.org/r/20231005002249.554877-1-jefferymiller@google.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>