[why] Current policy assumes virtual DPCD peer device as an individual MST branch device with 1 input and 1 output. However this is only true for virtual DP-to-DP peer device. In general there are three types of virtual DP peer devices. 1. Sink peer device with virtual DPCD. 2. Virtual DP-to-DP Peer device with virtual DPCD. 3. Virtual DP-to-HDMI Protocol Converter Peer Device with Virtual DPCD. So we should break the assumption and handle all three types. [how] DP-to-DP peer device will have virtual DPCD cap upstream. Sink peer device will have virtual DPCD on the logical port. Dp to HDMI protocol converter peer device will have virtual DPCD on its converter port. For DSC capable Synaptics non VGA port we workaround by enumerating a virutal DPCD peer device on its upstream even if it doesn't have one. Signed-off-by: Wenjing Liu <Wenjing.Liu@amd.com> Reviewed-by: Jun Lei <Jun.Lei@amd.com> Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.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.
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