Patch "drm/i915: reintroduce VLV/CHV PFI programming power domain workaround" has been added to the 4.12-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    drm/i915: reintroduce VLV/CHV PFI programming power domain workaround

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-i915-reintroduce-vlv-chv-pfi-programming-power-domain-workaround.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 9c75b185274b7766fe69c2e73607c1ed780b284b Mon Sep 17 00:00:00 2001
From: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Date: Wed, 28 Jun 2017 18:06:05 -0300
Subject: drm/i915: reintroduce VLV/CHV PFI programming power domain workaround
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

From: Gabriel Krisman Bertazi <krisman@collabora.co.uk>

commit 9c75b185274b7766fe69c2e73607c1ed780b284b upstream.

There are still cases on these platforms where an attempt is made to
configure the CDCLK while the power domain is off, like when coming back
from a suspend.  So the workaround below is still needed.

This effectively reverts commit 63ff30442519 ("drm/i915: Nuke the
VLV/CHV PFI programming power domain workaround").

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101517
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20170628210605.4994-1-krisman@collabora.co.uk
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
(cherry picked from commit 886015a0ad43c7fc034b23ea4614ba39162f9ddd)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/i915/intel_cdclk.c |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

--- a/drivers/gpu/drm/i915/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/intel_cdclk.c
@@ -491,6 +491,14 @@ static void vlv_set_cdclk(struct drm_i91
 	int cdclk = cdclk_state->cdclk;
 	u32 val, cmd;
 
+	/* There are cases where we can end up here with power domains
+	 * off and a CDCLK frequency other than the minimum, like when
+	 * issuing a modeset without actually changing any display after
+	 * a system suspend.  So grab the PIPE-A domain, which covers
+	 * the HW blocks needed for the following programming.
+	 */
+	intel_display_power_get(dev_priv, POWER_DOMAIN_PIPE_A);
+
 	if (cdclk >= 320000) /* jump to highest voltage for 400MHz too */
 		cmd = 2;
 	else if (cdclk == 266667)
@@ -549,6 +557,8 @@ static void vlv_set_cdclk(struct drm_i91
 	intel_update_cdclk(dev_priv);
 
 	vlv_program_pfi_credits(dev_priv);
+
+	intel_display_power_put(dev_priv, POWER_DOMAIN_PIPE_A);
 }
 
 static void chv_set_cdclk(struct drm_i915_private *dev_priv,
@@ -568,6 +578,14 @@ static void chv_set_cdclk(struct drm_i91
 		return;
 	}
 
+	/* There are cases where we can end up here with power domains
+	 * off and a CDCLK frequency other than the minimum, like when
+	 * issuing a modeset without actually changing any display after
+	 * a system suspend.  So grab the PIPE-A domain, which covers
+	 * the HW blocks needed for the following programming.
+	 */
+	intel_display_power_get(dev_priv, POWER_DOMAIN_PIPE_A);
+
 	/*
 	 * Specs are full of misinformation, but testing on actual
 	 * hardware has shown that we just need to write the desired
@@ -590,6 +608,8 @@ static void chv_set_cdclk(struct drm_i91
 	intel_update_cdclk(dev_priv);
 
 	vlv_program_pfi_credits(dev_priv);
+
+	intel_display_power_put(dev_priv, POWER_DOMAIN_PIPE_A);
 }
 
 static int bdw_calc_cdclk(int max_pixclk)


Patches currently in stable-queue which might be from krisman@collabora.co.uk are

queue-4.12/drm-i915-reintroduce-vlv-chv-pfi-programming-power-domain-workaround.patch