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path: root/drivers/gpu/drm/i915/i915_drv.h
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Diffstat (limited to 'drivers/gpu/drm/i915/i915_drv.h')
-rw-r--r--drivers/gpu/drm/i915/i915_drv.h21
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index c0f19f57200..2c192270cb0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1053,6 +1053,27 @@ struct drm_i915_file_private {
#include "i915_trace.h"
+/**
+ * RC6 is a special power stage which allows the GPU to enter an very
+ * low-voltage mode when idle, using down to 0V while at this stage. This
+ * stage is entered automatically when the GPU is idle when RC6 support is
+ * enabled, and as soon as new workload arises GPU wakes up automatically as well.
+ *
+ * There are different RC6 modes available in Intel GPU, which differentiate
+ * among each other with the latency required to enter and leave RC6 and
+ * voltage consumed by the GPU in different states.
+ *
+ * The combination of the following flags define which states GPU is allowed
+ * to enter, while RC6 is the normal RC6 state, RC6p is the deep RC6, and
+ * RC6pp is deepest RC6. Their support by hardware varies according to the
+ * GPU, BIOS, chipset and platform. RC6 is usually the safest one and the one
+ * which brings the most power savings; deeper states save more power, but
+ * require higher latency to switch to and wake up.
+ */
+#define INTEL_RC6_ENABLE (1<<0)
+#define INTEL_RC6p_ENABLE (1<<1)
+#define INTEL_RC6pp_ENABLE (1<<2)
+
extern struct drm_ioctl_desc i915_ioctls[];
extern int i915_max_ioctl;
extern unsigned int i915_fbpercrtc __always_unused;