2f015ec6ea
Unfortunately the DP MST helpers do not have much in the way of debugging utilities. So, let's add some! This adds basic debugging output for down sideband requests that we send from the driver, so that we can actually discern what's happening when sideband requests timeout. Since there wasn't really a good way of testing that any of this worked, I ended up writing simple selftests that lightly test sideband message encoding and decoding as well. Enjoy! Changes since v1: * Clean up DO_TEST() and sideband_msg_req_encode_decode() - danvet * Get rid of pr_fmt(), just define a prefix string instead and use drm_printf() * Check highest bit of VCPI in drm_dp_decode_sideband_req() - danvet * Make the switch case order between drm_dp_decode_sideband_req() and drm_dp_encode_sideband_req() the same - danvet * Only check DRM_UT_DP - danvet * Clean up sideband_msg_req_equal() from selftests a bit, and add comments explaining why we can't just use memcmp - danvet Cc: Juston Li <juston.li@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Harry Wentland <hwentlan@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190903204645.25487-8-lyude@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.