BACKPORT: usb: typec: altmodes/displayport: Signal hpd when configuring pin assignment

When connecting to some DisplayPort partners, the initial status update
after entering DisplayPort Alt Mode notifies that the DFP_D/UFP_D is not in
the connected state. This leads to sending a configure message that keeps
the device in USB mode. The port partner then sets DFP_D/UFP_D to the
connected state and HPD to high in the same Attention message. Currently,
the HPD signal is dropped in order to handle configuration.

This patch saves changes to the HPD signal when the device chooses to
configure during dp_altmode_status_update, and invokes sysfs_notify if
necessary for HPD after configuring.

Fixes: 0e3bb7d6 ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable@vger.kernel.org
Signed-off-by: RD Babiera <rdbabiera@google.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/all/20230726020903.1409072-1-rdbabiera@google.com/


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bug: 288137625
(cherry picked from commit 5a5ccd61)
[rd: resolved minor conflict in displayport.c]
Signed-off-by: RD Babiera <rdbabiera@google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:056a17677de932cccda77faf3f1c53a5b59c8cf5)
Merged-In: I26ef49949aa0681ea6b88d8c95f5ddd54fe84664
Change-Id: I26ef49949aa0681ea6b88d8c95f5ddd54fe84664