drm/i915: Extract i915gm_irq_cstate_wa_{disable,enable}()

Extract the i915gm/i945gm vblank irq C-state workaround to
separate functions. We'll need to reuse these in order to
guarantee timely CRC interrupt delivery as well.

The irq.vblank_enabled count is currently protected by the
drm vblank locks, so let's assert that the innermost of those
is held, in anticipation of other callers.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241001195803.3371-4-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_display_irq.c b/drivers/gpu/drm/i915/display/intel_display_irq.c
index 43a0b3565bc898d505851589c4e5e80c35704b3a..feeb3a29972a40508a278ffc2280cd088ad8b91f 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display_irq.c
+++ b/drivers/gpu/drm/i915/display/intel_display_irq.c
@@ -1259,6 +1259,28 @@ void gen11_display_irq_handler(struct drm_i915_private *i915)
        enable_rpm_wakeref_asserts(&i915->runtime_pm);
 }
 
+static void i915gm_irq_cstate_wa_enable(struct drm_i915_private *i915)
+{
+       lockdep_assert_held(&i915->drm.vblank_time_lock);
+
+       /*
+        * Vblank interrupts fail to wake the device up from C2+.
+        * Disabling render clock gating during C-states avoids
+        * the problem. There is a small power cost so we do this
+        * only when vblank interrupts are actually enabled.
+        */
+       if (i915->display.irq.vblank_enabled++ == 0)
+               intel_uncore_write(&i915->uncore, SCPD0, _MASKED_BIT_ENABLE(CSTATE_RENDER_CLOCK_GATE_DISABLE));
+}
+
+static void i915gm_irq_cstate_wa_disable(struct drm_i915_private *i915)
+{
+       lockdep_assert_held(&i915->drm.vblank_time_lock);
+
+       if (--i915->display.irq.vblank_enabled == 0)
+               intel_uncore_write(&i915->uncore, SCPD0, _MASKED_BIT_DISABLE(CSTATE_RENDER_CLOCK_GATE_DISABLE));
+}
+
 int i8xx_enable_vblank(struct drm_crtc *crtc)
 {
        struct drm_i915_private *dev_priv = to_i915(crtc->dev);
@@ -1287,14 +1309,7 @@ int i915gm_enable_vblank(struct drm_crtc *crtc)
 {
        struct drm_i915_private *i915 = to_i915(crtc->dev);
 
-       /*
-        * Vblank interrupts fail to wake the device up from C2+.
-        * Disabling render clock gating during C-states avoids
-        * the problem. There is a small power cost so we do this
-        * only when vblank interrupts are actually enabled.
-        */
-       if (i915->display.irq.vblank_enabled++ == 0)
-               intel_uncore_write(&i915->uncore, SCPD0, _MASKED_BIT_ENABLE(CSTATE_RENDER_CLOCK_GATE_DISABLE));
+       i915gm_irq_cstate_wa_enable(i915);
 
        return i8xx_enable_vblank(crtc);
 }
@@ -1305,8 +1320,7 @@ void i915gm_disable_vblank(struct drm_crtc *crtc)
 
        i8xx_disable_vblank(crtc);
 
-       if (--i915->display.irq.vblank_enabled == 0)
-               intel_uncore_write(&i915->uncore, SCPD0, _MASKED_BIT_DISABLE(CSTATE_RENDER_CLOCK_GATE_DISABLE));
+       i915gm_irq_cstate_wa_disable(i915);
 }
 
 int i965_enable_vblank(struct drm_crtc *crtc)