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drm/i915: relax uncritical udelay_range() settings

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udelay_range(2, 3) is inefficient and as discussions with Jani Nikula
<jani.nikula@linux.intel.com> unnecessary here. This replaces this
tight setting with a relaxed delay of min=20 and max=50. which helps
the hrtimer subsystem optimize timer handling.

Link: http://lkml.org/lkml/2016/12/15/127
Fixes: commit 37ab0810c9b7 ("drm/i915/bxt: DSI enable for BXT")
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1481853560-19795-1-git-send-email-hofrat@osadl.org
This commit is contained in:
Nicholas Mc Guire 2016-12-16 02:59:20 +01:00 committed by Jani Nikula
parent 776594d528
commit 0a7b35ce2e
1 changed files with 2 additions and 1 deletions
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3
drivers/gpu/drm/i915/intel_dsi.c
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@ -379,7 +379,8 @@ static void bxt_dsi_device_ready(struct intel_encoder *encoder)
val &= ~ULPS_STATE_MASK;
val |= (ULPS_STATE_ENTER | DEVICE_READY);
I915_WRITE(MIPI_DEVICE_READY(port), val);
usleep_range(2, 3);
/* at least 2us - relaxed for hrtimer subsystem optimization */
usleep_range(10, 50);
/* 3. Exit ULPS */
val = I915_READ(MIPI_DEVICE_READY(port));