Commit 9c754024 authored Nov 02, 2016 by Dhinakaran Pandiyan Committed by Jani Nikula Nov 04, 2016

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

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


Cc: stable@vger.kernel.org
Cc: Libin Yang <libin.yang@linux.intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1478117601-19122-1-git-send-email-dhinakaran.pandiyan@intel.com

parent b30ce9e0

drivers/gpu/drm/i915/intel_display.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -10250,8 +10250,10 @@ static void bxt_modeset_commit_cdclk(struct drm_atomic_state *old_state)
		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
		@@ -10293,7 +10295,7 @@ static int ilk_max_pixel_rate(struct drm_atomic_state *state)

		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);