drm/i915: Disable runtime power management during shutdown

commit 7962893ecb853aa7c8925ce237ab6c4274cfc1c7 upstream.

At least on some TGL platforms PUNIT wants to access some display HW
registers, but it doesn't handle display power management (disabling DC
states as required) and so this register access will lead to a hang. To
prevent this disable runtime power management for poweroff and reboot.

v2:
- Add code comment clarifying the requirement of display power states.
  (Ville)

Reported-and-tested-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Khaled Almahallawy <khaled.almahallawy@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210127181909.128094-1-imre.deak@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 8e9cb44e66e530914801b1a43c5c5a454efe41ab..4ecb813c9bc7d0a06e80150d96c089292de691e7 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1049,6 +1049,8 @@ static void intel_shutdown_encoders(struct drm_i915_private *dev_priv)
 void i915_driver_shutdown(struct drm_i915_private *i915)
 {
        disable_rpm_wakeref_asserts(&i915->runtime_pm);
+       intel_runtime_pm_disable(&i915->runtime_pm);
+       intel_power_domains_disable(i915);
 
        i915_gem_suspend(i915);
 
@@ -1064,7 +1066,15 @@ void i915_driver_shutdown(struct drm_i915_private *i915)
        intel_suspend_encoders(i915);
        intel_shutdown_encoders(i915);
 
+       /*
+        * The only requirement is to reboot with display DC states disabled,
+        * for now leaving all display power wells in the INIT power domain
+        * enabled matching the driver reload sequence.
+        */
+       intel_power_domains_driver_remove(i915);
        enable_rpm_wakeref_asserts(&i915->runtime_pm);
+
+       intel_runtime_pm_driver_release(&i915->runtime_pm);
 }
 
 static bool suspend_to_idle(struct drm_i915_private *dev_priv)