3d3721ccb1
We're going to be doing the same probing process in nouveau for determining downstream DP port capabilities, so let's deduplicate the work by moving i915's code for handling this into a shared helper: drm_dp_read_downstream_info(). Note that when we do this, we also do make some functional changes while we're at it: * We always clear the downstream port info before trying to read it, just to make things easier for the caller * We skip reading downstream port info if the DPCD indicates that we don't support downstream port info * We only read as many bytes as needed for the reported number of downstream ports, no sense in reading the whole thing every time v2: * Fixup logic for calculating the downstream port length to account for the fact that downstream port caps can be either 1 byte or 4 bytes long. We can actually skip fixing the max_clock/max_bpc helpers here since they all check for DP_DETAILED_CAP_INFO_AVAILABLE anyway. * Fix ret code check for drm_dp_dpcd_read v5: * Change name from drm_dp_downstream_read_info() to drm_dp_read_downstream_info() * Also, add "See Also" sections for the various downstream info functions (drm_dp_read_downstream_info(), drm_dp_downstream_max_clock(), drm_dp_downstream_max_bpc()) Reviewed-by: Sean Paul <sean@poorly.run> Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200826182456.322681-14-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.