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| /linux/drivers/gpu/drm/i915/display/ |
| H A D | intel_audio.c | diff f4b18892dca8e629e0ce192b233579505f8ed343 Tue Dec 31 15:00:07 CET 2019 Kai Vehmanen <kai.vehmanen@linux.intel.com> drm/i915: Limit audio CDCLK>=2*BCLK constraint back to GLK only
Revert changes done in commit f6ec9483091f ("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: f6ec9483091f ("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
(cherry picked from commit 1ee48a61aa57dbdbc3cd2808d8b28df40d938e44)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
diff 1ee48a61aa57dbdbc3cd2808d8b28df40d938e44 Tue Dec 31 15:00:07 CET 2019 Kai Vehmanen <kai.vehmanen@linux.intel.com> drm/i915: Limit audio CDCLK>=2*BCLK constraint back to GLK only
Revert changes done in commit f6ec9483091f ("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: f6ec9483091f ("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
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