drm/i915: fix regression leading to display audio probe failure on GLK

In commit b800c9a3ae6e ("drm/i915: Extract cdclk requirements checking
to separate function") the order of force_min_cdclk_changed check and
intel_modeset_checks(), was reversed. This broke the mechanism to
immediately force a new CDCLK minimum, and lead to driver probe
errors for display audio on GLK platform with 5.9-rc1 kernel. Fix
the issue by moving intel_modeset_checks() call later.

[vsyrjala: It also broke the ability of planes to bump up the cdclk
and thus could lead to underruns when eg. flipping from 32bpp to
64bpp framebuffer. To be clear, we still compute the new cdclk
correctly but fail to actually program it to the hardware due to
intel_set_cdclk_{pre,post}_plane_update() not getting called on
account of state->modeset==false.]

Fixes: b800c9a3ae6e ("drm/i915: Extract cdclk requirements checking to separate function")
BugLink: https://github.com/thesofproject/linux/issues/2410
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200901151036.1312357-1-kai.vehmanen@linux.intel.com
(cherry picked from commit cf696856bc54a31f78e6538b84c8f7a006b6108b)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 68325678f5ef92eb866fc9c456e13a4d95688a5d..b18c5ac2934dcb19e27fc38f667bf38b180a337e 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -14956,12 +14956,6 @@ static int intel_atomic_check(struct drm_device *dev,
        if (dev_priv->wm.distrust_bios_wm)
                any_ms = true;
 
-       if (any_ms) {
-               ret = intel_modeset_checks(state);
-               if (ret)
-                       goto fail;
-       }
-
        intel_fbc_choose_crtc(dev_priv, state);
        ret = calc_watermark_data(state);
        if (ret)
@@ -14976,6 +14970,10 @@ static int intel_atomic_check(struct drm_device *dev,
                goto fail;
 
        if (any_ms) {
+               ret = intel_modeset_checks(state);
+               if (ret)
+                       goto fail;
+
                ret = intel_modeset_calc_cdclk(state);
                if (ret)
                        return ret;