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

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
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
(cherry picked from commit 9c7540241885838cfc7fa58c4a8bd75be0303ed1)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3bc929e007aaf8a8504ad1db7123b0691ef7fba1..e26f88965c5836b63a44023ad4720d66d5f056e2 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9740,8 +9740,10 @@ 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
@@ -9783,7 +9785,7 @@ 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);