From 0126336af286ea85c1137ad13882f8c93d74c6c3 Mon Sep 17 00:00:00 2001
From: Fedora Kernel Team <kernel-team@fedoraproject.org>
Date: Mon, 20 Jun 2016 12:40:13 +0200
Subject: [PATCH 08/17] drm/i915: Add distrust_bios_wm flag to dev_priv (v2)

Upstream: since drm-intel-next-2016-05-22
commit 279e99d76e6097ee7b531114777fa9b030496d81

Author:     Matt Roper <matthew.d.roper@intel.com>
AuthorDate: Thu May 12 07:06:02 2016 -0700
Commit:     Matt Roper <matthew.d.roper@intel.com>
CommitDate: Fri May 13 07:33:54 2016 -0700

    drm/i915: Add distrust_bios_wm flag to dev_priv (v2)

    SKL-style platforms can't fully trust the watermark/DDB settings
    programmed by the BIOS and need to do extra sanitization on their first
    atomic update.  Add a flag to dev_priv that is set during hardware
    readout and cleared at the end of the first commit.

    Note that for the somewhat common case where everything is turned off
    when the driver starts up, we don't need to bother with a recompute...we
    know exactly what the DDB should be (all zero's) so just setup the DDB
    directly in that case.

    v2:
     - Move clearing of distrust_bios_wm up below the swap_state call since
       it's a more natural / self-explanatory location.  (Maarten)
     - Use dev_priv->active_crtcs to test whether any CRTC's are turned on
       during HW WM readout rather than trying to count the active CRTC's
       again ourselves.  (Maarten)

    Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
    Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
    Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
    Link: http://patchwork.freedesktop.org/patch/msgid/1463061971-19638-9-git-send-email-matthew.d.roper@intel.com
---
 drivers/gpu/drm/i915/i915_drv.h      | 7 +++++++
 drivers/gpu/drm/i915/intel_display.c | 1 +
 drivers/gpu/drm/i915/intel_pm.c      | 8 ++++++++
 3 files changed, 16 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 804af6f..ae7932a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1986,6 +1986,13 @@ struct drm_i915_private {
 		};
 
 		uint8_t max_level;
+
+		/*
+		 * Set during HW readout of watermarks/DDB.  Some platforms
+		 * need to know when we're still using BIOS-provided values
+		 * (which we don't fully trust).
+		 */
+		bool distrust_bios_wm;
 	} wm;
 
 	struct i915_runtime_pm pm;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f53df81..786f3d9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13516,6 +13516,7 @@ static int intel_atomic_commit(struct drm_device *dev,
 
 	drm_atomic_helper_swap_state(dev, state);
 	dev_priv->wm.config = to_intel_atomic_state(state)->wm_config;
+	dev_priv->wm.distrust_bios_wm = false;
 
 	if (intel_state->modeset) {
 		memcpy(dev_priv->min_pixclk, intel_state->min_pixclk,
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index ee82b1f..6a09d7a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3967,6 +3967,14 @@ void skl_wm_get_hw_state(struct drm_device *dev)
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
 		skl_pipe_wm_get_hw_state(crtc);
 
+	if (dev_priv->active_crtcs) {
+		/* Fully recompute DDB on first atomic commit */
+		dev_priv->wm.distrust_bios_wm = true;
+	} else {
+		/* Easy/common case; just sanitize DDB now if everything off */
+		memset(ddb, 0, sizeof(*ddb));
+	}
+
 	/* Calculate plane data rates */
 	for_each_intel_crtc(dev, intel_crtc) {
 		struct intel_crtc_state *cstate = intel_crtc->config;
-- 
2.7.4