[Intel-gfx] [PATCH v2 15/25] drm/i915: disable runtime PM if RC6 is disabled

[Imre Deak]

On VLV we depend on RC6 to save the GT render and media HW context
before going to the D3 state via RPM, so as a preparation for the
VLV RPM support (added in an upcoming patch) disable RPM if RC6 is
disabled.

There is probably a similar dependency on other platforms too, so for
safety require RC6 for those too. For these platforms (SNB, HSW, BDW)
this is then a possible fix.

v2:
- require RC6 for all RPM platforms, not just for VLV (Paulo, Daniel)

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c |  2 +-
 drivers/gpu/drm/i915/intel_pm.c | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index a20d2d1..43980c9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -923,7 +923,7 @@ static int intel_runtime_suspend(struct device *device)
 	struct drm_device *dev = pci_get_drvdata(pdev);
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	if (WARN_ON_ONCE(!dev_priv->rps.enabled))
+	if (WARN_ON_ONCE(!(dev_priv->rps.enabled && intel_enable_rc6(dev))))
 		return -ENODEV;
 
 	WARN_ON(!HAS_RUNTIME_PM(dev));
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 89fe0a7..3068f51 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6098,6 +6098,15 @@ void intel_init_runtime_pm(struct drm_i915_private *dev_priv)
 
 	pm_runtime_set_active(device);
 
+	/*
+	 * RPM depends on RC6 to save restore the GT HW context, so make RC6 a
+	 * requirement.
+	 */
+	if (!intel_enable_rc6(dev)) {
+		DRM_INFO("RC6 disabled, disabling runtime PM support\n");
+		return;
+	}
+
 	pm_runtime_set_autosuspend_delay(device, 10000); /* 10s */
 	pm_runtime_mark_last_busy(device);
 	pm_runtime_use_autosuspend(device);
@@ -6113,6 +6122,9 @@ void intel_fini_runtime_pm(struct drm_i915_private *dev_priv)
 	if (!HAS_RUNTIME_PM(dev))
 		return;
 
+	if (!intel_enable_rc6(dev))
+		return;
+
 	/* Make sure we're not suspended first. */
 	pm_runtime_get_sync(device);
 	pm_runtime_disable(device);
-- 
1.8.4