From 0a7b35ce2e7a8744ff2b7689f09bd4f5e00e77f1 Mon Sep 17 00:00:00 2001 From: Nicholas Mc Guire Date: Fri, 16 Dec 2016 02:59:20 +0100 Subject: [PATCH] drm/i915: relax uncritical udelay_range() settings udelay_range(2, 3) is inefficient and as discussions with Jani Nikula 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 Reviewed-by: Jani Nikula Signed-off-by: Jani Nikula Link: http://patchwork.freedesktop.org/patch/msgid/1481853560-19795-1-git-send-email-hofrat@osadl.org --- drivers/gpu/drm/i915/intel_dsi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c index 0668bbec5028..c978852904ed 100644 --- a/drivers/gpu/drm/i915/intel_dsi.c +++ b/drivers/gpu/drm/i915/intel_dsi.c @@ -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)); -- 2.20.1