1bdcffaa0d
commit 06f66261a1567d66b9d35c87393b6edfbea4c8f8 upstream. At least restoring the MST topology during system resume needs to use AUX before the display HW readout->sanitization sequence is complete, but on TC ports the PHY may be in the wrong mode for this, resulting in the AUX transfers to fail. The initial TC port mode is kept fixed as BIOS left it for the above HW readout sequence (to prevent changing the mode on an enabled port). If the port is disabled this initial mode is TBT - as in any case the PHY ownership is not held - even if a DP-alt sink is connected. Thus, the AUX transfers during this time will use TBT mode instead of the expected DP-alt mode and so time out. Fix the above by connecting the PHY during port initialization if the port is disabled, which will switch to the expected mode (DP-alt in the above case). As the encoder/pipe HW state isn't read-out yet at this point, check if the port is enabled based on the DDI_BUF enabled flag. Save the read-out initial mode, so intel_tc_port_sanitize_mode() can check this wrt. the read-out encoder HW state. Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230316131724.359612-5-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.