Patch "drm/i915/dp: Extend BDW DP audio workaround to GEN9 platforms" has been added to the 4.8-stable tree

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

drm/i915/dp: Extend BDW DP audio workaround to GEN9 platforms

to the 4.8-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-dp-extend-bdw-dp-audio-workaround-to-gen9-platforms.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dhinakaran Pandiyan <[email protected]>
Date: Wed, 2 Nov 2016 13:13:21 -0700
Subject: drm/i915/dp: Extend BDW DP audio workaround to GEN9 platforms

From: Dhinakaran Pandiyan <[email protected]>

commit 61e0c5438866d0e737937fc35d752538960e1e9f upstream.

According to BSpec, cdclk for BDW has to be not less than 432 MHz with DP audio enabled, port width x4, and link rate HBR2 (5.4 GHz). With cdclk less than 432 MHz, enabling audio leads to pipe FIFO underruns and displays cycling on/off.

Let's apply this work around to GEN9 platforms too, as it fixes the same issue.

v2: Move drm_device to drm_i915_private conversion

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97907

---
 drivers/gpu/drm/i915/intel_display.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -9740,8 +9740,10 @@ static void bxt_modeset_commit_cdclk(str
 static int bdw_adjust_min_pipe_pixel_rate(struct intel_crtc_state *crtc_state,
 					  int pixel_rate)
 {
+	struct drm_i915_private *dev_priv = to_i915(crtc_state->base.crtc->dev);
+
 	/* pixel rate mustn't exceed 95% of cdclk with IPS on BDW */
-	if (crtc_state->ips_enabled)
+	if (IS_BROADWELL(dev_priv) && crtc_state->ips_enabled)
 		pixel_rate = DIV_ROUND_UP(pixel_rate * 100, 95);
 
 	/* BSpec says "Do not use DisplayPort with CDCLK less than

@@ -9783,7 +9785,7 @@ static int ilk_max_pixel_rate(struct drm
 
 		pixel_rate = ilk_pipe_pixel_rate(crtc_state);
 
-		if (IS_BROADWELL(dev_priv))
+		if (IS_BROADWELL(dev_priv) || IS_GEN9(dev_priv))
 			pixel_rate = bdw_adjust_min_pipe_pixel_rate(crtc_state,
 								    pixel_rate);
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/drm-i915-dp-bdw-cdclk-fix-for-dp-audio.patch queue-4.8/drm-i915-dp-extend-bdw-dp-audio-workaround-to-gen9-platforms.patch