releases/4.8.17/drm-i915-fix-cdclk-vs.-dev_cdclk-mess-when-not-recomputing-things.patch

From 14676ec6b1a6f2f7fa0bafd98ab42ce77be7a7d4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Mon, 14 Nov 2016 18:35:09 +0200
Subject: drm/i915: Fix cdclk vs. dev_cdclk mess when not recomputing things
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From: Ville Syrjälä <ville.syrjala@linux.intel.com>

commit 14676ec6b1a6f2f7fa0bafd98ab42ce77be7a7d4 upstream.

When we end up not recomputing the cdclk, we need to populate
intel_state->cdclk with the "atomic_cdclk_freq" instead of the
current cdclk_freq. When no pipes are active, the actual cdclk_freq
may be lower than what the configuration of the planes and
pipes would require from the point of view of the software state.

This fixes bogus WARNS from skl_max_scale() which is trying to check
the plane software state against the cdclk frequency. So any time
it got called during DPMS off for instance, we might have tripped
the warn if the current mode would have required a higher than
minimum cdclk.

v2: Drop the dev_cdclk stuff (Maarten)

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Mika Kahola <mika.kahola@intel.com>
Cc: bruno.pagani@ens-lyon.org
Cc: Daniel J Blueman <daniel.blueman@gmail.com>
Cc: Paul Bolle <pebolle@tiscali.nl>
Cc: Joseph Yasi <joe.yasi@gmail.com>
Tested-by: Paul Bolle <pebolle@tiscali.nl>
Tested-by: Joseph Yasi <joe.yasi@gmail.com> (v1)
Fixes: 1a617b77658e ("drm/i915: Keep track of the cdclk as if all crtc's were active.")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98214
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1479141311-11904-2-git-send-email-ville.syrjala@linux.intel.com
(cherry picked from commit e0ca7a6be38ce603d26df5707c22e53870a623e0)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/i915/intel_display.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13494,8 +13494,9 @@ static int intel_modeset_checks(struct d
 
 		DRM_DEBUG_KMS("New cdclk calculated to be atomic %u, actual %u\n",
 			      intel_state->cdclk, intel_state->dev_cdclk);
-	} else
+	} else {
 		to_intel_atomic_state(state)->cdclk = dev_priv->atomic_cdclk_freq;
+	}
 
 	intel_modeset_clear_plls(state);
 
@@ -13596,8 +13597,9 @@ static int intel_atomic_check(struct drm
 
 		if (ret)
 			return ret;
-	} else
-		intel_state->cdclk = dev_priv->cdclk_freq;
+	} else {
+		intel_state->cdclk = dev_priv->atomic_cdclk_freq;
+	}
 
 	ret = drm_atomic_helper_check_planes(dev, state);
 	if (ret)