drm/i915/fbc: Introduce intel_fbc_sanitize()

Let's make sure FBC is always disabled when we start to take
over the hardware state.

I suspect this should never really happen, since the only time
when we really should be taking over with the display already
active is when the previous state was progammed by the BIOS,
which likely shouldn't use FBC. This could be driver init,
or S4 resume when the boot kernel doesn't load i915. But I
suppose no harm in keeping this code around for exra safety
since it's quite trivial.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220315140001.1172-7-ville.syrjala@linux.intel.com
Reviewed-by: Mika Kahola <mika.kahola@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 5b020ff899084c8f43ed050f0277987836d0ad84..29044cf58b87d1f7f630d1f3039937a21a35b24e 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -10430,6 +10430,8 @@ intel_modeset_setup_hw_state(struct drm_device *dev,
                        intel_crtc_vblank_on(crtc_state);
        }
 
+       intel_fbc_sanitize(dev_priv);
+
        intel_sanitize_plane_mapping(dev_priv);
 
        for_each_intel_encoder(dev, encoder)

diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
index 79be87cfe9e505c08f7b8eb6d474cbda1b5b5af0..040098ef18bc7ae4916633b65f8f6e53a5efee33 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_fbc.c
+++ b/drivers/gpu/drm/i915/display/intel_fbc.c
@@ -1703,22 +1703,26 @@ void intel_fbc_init(struct drm_i915_private *i915)
        drm_dbg_kms(&i915->drm, "Sanitized enable_fbc value: %d\n",
                    i915->params.enable_fbc);
 
-       for_each_fbc_id(i915, fbc_id) {
-               struct intel_fbc *fbc;
+       for_each_fbc_id(i915, fbc_id)
+               i915->fbc[fbc_id] = intel_fbc_create(i915, fbc_id);
+}
 
-               fbc = intel_fbc_create(i915, fbc_id);
-               if (!fbc)
-                       continue;
+/**
+ * intel_fbc_sanitize - Sanitize FBC
+ * @i915: the i915 device
+ *
+ * Make sure FBC is initially disabled since we have no
+ * idea eg. into which parts of stolen it might be scribbling
+ * into.
+ */
+void intel_fbc_sanitize(struct drm_i915_private *i915)
+{
+       struct intel_fbc *fbc;
+       enum intel_fbc_id fbc_id;
 
-               /*
-                * We still don't have any sort of hardware state readout
-                * for FBC, so deactivate it in case the BIOS activated it
-                * to make sure software matches the hardware state.
-                */
+       for_each_intel_fbc(i915, fbc, fbc_id) {
                if (intel_fbc_hw_is_active(fbc))
                        intel_fbc_hw_deactivate(fbc);
-
-               i915->fbc[fbc->id] = fbc;
        }
 }
 

diff --git a/drivers/gpu/drm/i915/display/intel_fbc.h b/drivers/gpu/drm/i915/display/intel_fbc.h
index 29e4216c27990d79b711c370d0bfeba8b3af0a69..db60143295ec6584ea54832035a2b02873f0ccf0 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_fbc.h
+++ b/drivers/gpu/drm/i915/display/intel_fbc.h
@@ -30,6 +30,7 @@ void intel_fbc_post_update(struct intel_atomic_state *state,
                           struct intel_crtc *crtc);
 void intel_fbc_init(struct drm_i915_private *dev_priv);
 void intel_fbc_cleanup(struct drm_i915_private *dev_priv);
+void intel_fbc_sanitize(struct drm_i915_private *dev_priv);
 void intel_fbc_update(struct intel_atomic_state *state,
                      struct intel_crtc *crtc);
 void intel_fbc_disable(struct intel_crtc *crtc);