drm/i915/skl: Ensure HW is powered during DDB HW state readout

The assumption when adding the intel_display_power_is_enabled() checks
was that if it returns success the power can't be turned off afterwards
during the HW access, which is guaranteed by modeset locks. This isn't
always true, so make sure we hold a dedicated reference for the time of
the access.

Spotted-by: Mika Kuoppala <[email protected]>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93441
CC: Chris Wilson <[email protected]>
Signed-off-by: Imre Deak <[email protected]>
Reviewed-by: Mika Kuoppala <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]
(cherry picked from commit 4d800030238878c1a98d1d3a37a3d673eea661ce)
Signed-off-by: Jani Nikula <[email protected]>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index a234687792f0b3be15b98ad08b84743135eac5ce..b28c29f20e754ec740e5aacd101bbe07867f65a6 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2829,7 +2829,10 @@ void skl_ddb_get_hw_state(struct drm_i915_private *dev_priv,
        memset(ddb, 0, sizeof(*ddb));
 
        for_each_pipe(dev_priv, pipe) {
-               if (!intel_display_power_is_enabled(dev_priv, POWER_DOMAIN_PIPE(pipe)))
+               enum intel_display_power_domain power_domain;
+
+               power_domain = POWER_DOMAIN_PIPE(pipe);
+               if (!intel_display_power_get_if_enabled(dev_priv, power_domain))
                        continue;
 
                for_each_plane(dev_priv, pipe, plane) {
@@ -2841,6 +2844,8 @@ void skl_ddb_get_hw_state(struct drm_i915_private *dev_priv,
                val = I915_READ(CUR_BUF_CFG(pipe));
                skl_ddb_entry_init_from_hw(&ddb->plane[pipe][PLANE_CURSOR],
                                           val);
+
+               intel_display_power_put(dev_priv, power_domain);
        }
 }