This attempts to enable all the available power wells during the
initialization.
Those power wells can be enabled in parallel or on-demand, and disabled
when no longer needed, but this is out of scope of this initial
enablement. Proper tracking of who uses which power well will require
a considerable rework of our display handling, so we just leave them all
enabled when the driver is loaded for now.
Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b01afb0..cc2be0b 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9635,6 +9635,34 @@ void intel_modeset_init_hw(struct drm_device *dev)
ivb_pch_pwm_override(dev);
}
+/* Starting with Haswell, we have different power wells for
+ * different parts of the GPU. This attempts to enable them all.
+ */
+static void intel_init_power_wells(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ unsigned long power_wells[] = {
+ HSW_PWR_WELL_CTL1,
+ HSW_PWR_WELL_CTL2,
+ HSW_PWR_WELL_CTL4
+ };
+ int i;
+
+ mutex_lock(&dev->struct_mutex);
+
+ for (i = 0; i < ARRAY_SIZE(power_wells); i++) {
+ int well = I915_READ(power_wells[i]);
+
+ if ((well & HSW_PWR_WELL_STATE) == 0) {
+ I915_WRITE(power_wells[i], well & HSW_PWR_WELL_ENABLE);
+ if (wait_for(I915_READ(power_wells[i] & HSW_PWR_WELL_STATE), 20))
+ DRM_ERROR("Error enabling power well %lx\n", power_wells[i]);
+ }
+ }
+
+ mutex_unlock(&dev->struct_mutex);
+}
+
void intel_modeset_init(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -9652,6 +9680,9 @@ void intel_modeset_init(struct drm_device *dev)
intel_init_quirks(dev);
+ if (IS_HASWELL(dev))
+ intel_init_power_wells(dev);
+
intel_init_display(dev);
if (IS_GEN2(dev)) {
--
1.7.10
