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.
v2: use more generic and future-proof code
Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com>
---
drivers/gpu/drm/i915/intel_pm.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 21587f8..bd9549d 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3559,6 +3559,37 @@ void intel_sanitize_pm(struct drm_device *dev)
dev_priv->display.sanitize_pm(dev);
}
+/* Starting with Haswell, we have different power wells for
+ * different parts of the GPU. This attempts to enable them all.
+ */
+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;
+
+ if (!IS_HASWELL(dev))
+ return;
+
+ 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);
+}
+
/* Set up chip specific power management-related functions */
void intel_init_pm(struct drm_device *dev)
{
@@ -3707,5 +3738,10 @@ void intel_init_pm(struct drm_device *dev)
else
dev_priv->display.get_fifo_size = i830_get_fifo_size;
}
+
+ /* We attempt to init the necessary power wells early in the initialization
+ * time, so the subsystems that expect power to be enabled can work.
+ */
+ intel_init_power_wells(dev);
}
--
1.7.10
