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Kai Vehmanen
1ee48a61aa
Revert changes done in commitf6ec948309("drm/i915: extend audio CDCLK>=2*BCLK constraint to more platforms"). Audio drivers communicate with i915 over HDA bus multiple times during system boot-up and each of these transactions result in matching get_power/put_power calls to i915, and depending on the platform, a modeset change causing visible flicker. GLK is the only platform with minimum CDCLK significantly lower than BCLK, and thus for GLK setting a higher CDCLK is mandatory. For other platforms, minimum CDCLK is close but below 2*BCLK (e.g. on ICL, CDCLK=176.4kHz with BCLK=96kHz). Spec-wise the constraint should be set, but in practise no communication errors have been reported and the downside if set is the flicker observed at boot-time. Revert to old behaviour until better mechanism to manage probe-time clocks is available. The full CDCLK>=2*BCLK constraint is still enforced at pipe enable time in intel_crtc_compute_min_cdclk(). Bugzilla: https://gitlab.freedesktop.org/drm/intel/issues/913 Fixes:f6ec948309("drm/i915: extend audio CDCLK>=2*BCLK constraint to more platforms") Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com> Reviewed-by: Matt Roper <matthew.d.roper@intel.com> Signed-off-by: Matt Roper <matthew.d.roper@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191231140007.31728-1-kai.vehmanen@linux.intel.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.