| commit | 8d5c24dddd04392e78578a41e574e15a487e3033 | [log] [tgz] |
|---|---|---|
| author | Angel Pons <th3fanbus@gmail.com> | Mon Mar 01 15:59:58 2021 +0100 |
| committer | Nico Huber <nico.h@gmx.de> | Tue May 11 12:12:18 2021 +0000 |
| tree | f0a8de3546d832459dfaec2051b395fe8d230bd1 | |
| parent | 0a8174bdf23ad947e85de7cadbaa0e5fd6d6e290 [diff] |
Add support to switch LSPCON modes LSPCON is a level shifter and protocol converter chip. It is principally used to convert DisplayPort into HDMI 2.0, since some Intel iGPUs do not have native HDMI 2.0 support. The chip defaults to LS mode, in which the display engine has to generate an HDMI-protocol signal, which the LSPCON converts from DisplayPort signal levels to HDMI signal levels. Add code to detect LSPCON chips and put them in protocol-converter mode. This way, the LSPCON behaves like a regular DisplayPort sink. This needs to be done before any DPCD accesses, because the LSPCON does not respond to DPCD accesses in level-shifter mode. Tested on Purism Librem Mini v1 (WHL-U), HDMI port can now light up. Change-Id: Idfa9bdff47a6591000cd5092d64a4cd4f8dbdc8d Signed-off-by: Angel Pons <th3fanbus@gmail.com> Reviewed-on: https://review.coreboot.org/c/libgfxinit/+/51133 Reviewed-by: Matt DeVillier <matt.devillier@gmail.com> Reviewed-by: Nico Huber <nico.h@gmx.de>
libgfxinit is a graphics initialization (aka modesetting) library for embedded environments. It currently supports only Intel hardware, more specifically the Intel Core processor line.
It can query and set up most kinds of displays based on their EDID information. You can, however, also specify particular mode lines.
libgfxinit is written in SPARK, an Ada subset with formal verifica- tion aspects. Absence of runtime errors can be proved automatically with SPARK GPL 2016.
For compilation, the GNAT Ada compiler is required. Usual package names in Linux distributions are gcc-ada and gnat.
You'll need libhwbase and libgfxinit. Best is to clone the reposi- tories into a common parent directory (this way libgfxinit will know where to find libhwbase).
$ mkdir gfxfun && cd gfxfun $ git clone https://review.coreboot.org/p/libhwbase.git $ git clone https://review.coreboot.org/p/libgfxinit.git
Both libraries are currently configured by hand-written config files. You can either write your own .config, link one of the shipped files in configs/, e.g.:
$ ln -s configs/linux libhwbase/.config
or overwrite the config filename by specifying cnf=<configfile> on the make command line.
By default most debug messages won't be compiled into the binary. To include them into the build, set DEBUG=1 on the command line or in your .config.
Let's install libhwbase. We'll need configs/linux to build regular Linux executables:
$ cd libhwbase $ make DEBUG=1 cnf=configs/linux install
By default this installs into a new subdirectory dest. You can however overwrite this decision by specifying DESTDIR=.
gfx_testlibgfxinit is configured and installed in the same manner as de- scribed above. You will have to select a configuration matching your hardware.
The makefile knows an additional target gfx_test to build a small Linux test application:
$ cd ../libgfxinit $ make DEBUG=1 cnf=configs/sandybridge gfx_test
The resulting binary is build/gfx_test.
gfx_test sets up its own framebuffer in the stolen memory. It backs any current framebuffer mapping and contents up first and re- stores it before exiting. This works somehow even while the i915 driver is running. A wrapper script gfxtest/gfx_test.sh is pro- vided to help with the setup. It switches to a text console first and tries to unload the i915 driver. But ignores failures to do so (it won't work if you still have any application running that uses the gfx driver, e.g. an X server).
# gfxtest/gfx_test.sh
If you chose the right config above, you should be presented with a nice test image. But please be prepared that your console might be stuck in that state afterwards. You can try to run it with i915 deactivated then (e.g. when booting with nomodeset in the kernel command line or with i915 blacklisted) and loading it afterwards.