bffb31f73b
On VLV/CHV there is some kind of linkage between the cdclk frequency and the DP link frequency. The spec says: "For DP audio configuration, cdclk frequency shall be set to meet the following requirements: DP Link Frequency(MHz) | Cdclk frequency(MHz) 270 | 320 or higher 162 | 200 or higher" I suspect that would more accurately be expressed as "cdclk >= DP link clock", and in any case we can express it like that in the code because of the limited set of cdclk (200, 266, 320, 400 MHz) and link frequencies (162 and 270 MHz) we support. Without this we can end up in a situation where the cdclk is too low and enabling DP audio will kill the pipe. Happens eg. with 2560x1440 modes where the 266MHz cdclk is sufficient to pump the pixels (241.5 MHz dotclock) but is too low for the DP audio due to the link frequency being 270 MHz. v2: Spell out the cdclk and link frequencies we actually support Cc: stable@vger.kernel.org Tested-by: Stefan Gottwald <gottwald@igel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111149 Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190717114536.22937-1-ville.syrjala@linux.intel.com Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
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.