drm/i915/cnl: Mask previous DDI - PLL mapping

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Without masking out the old value, we can end up pointing the DDI to a
disabled PLL, which makes the system fall over. Mask out the previous
value before setting the PLL to DDI mapping.

This can be observed by running igt/testdisplay with both an eDP and
HDMI/DP output active.

v2: Add the Bugzilla link

Fixes: 555e38d273 ("drm/i915/cnl: DDI - PLL mapping")
Testcase: igt/testdisplay
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103997
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Matt Atwood <matthew.s.atwood@intel.com>
Signed-off-by: James Ausmus <james.ausmus@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Tested-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171201021700.13504-1-james.ausmus@intel.com
(cherry picked from commit 23a7068ec5)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

...

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James Ausmus 2017-11-30 18:17:00 -08:00 • committed by Joonas Lahtinen

parent a87e55f89f

commit 46442beed9

1 changed files with 1 additions and 0 deletions

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drivers/gpu/drm/i915/intel_ddi.c

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