4e79e12f5b
On some Cherry Trail devices, DisplayPort over Type-C is supported through a USB-PD microcontroller (e.g. a fusb302) + a mux to switch the superspeed datalines between USB-3 and DP (e.g. a pi3usb30532). The kernel in this case does the PD/alt-mode negotiation itself, rather then everything being handled in firmware. So the kernel itself picks an alt-mode, tells the Type-C "dongle" to switch to DP mode and sets the mux accordingly. In this setup the HPD pin is not connected, so the i915 driver needs to respond to a software event and scan the DP port for changes manually. This commit adds support for this. Together with the recent addition of DP alt-mode support to the Type-C subsystem this makes DP over Type-C work on these devices. Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20210817215201.795062-7-hdegoede@redhat.com
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.