drm/i915: Scale ring, rather than ia, frequency on Haswell
Haswell introduces a separate frequency domain for the ring (uncore). So
where we used to increase the CPU (IA) clock with GPU busyness, we now
need to scale the ring frequency directly instead. As the ring limits
our memory bandwidth, it is vital for performance that when the GPU is
busy, we increase the frequency of the ring to increase the available
memory bandwidth.
v2: Fix the algorithm to actually use the scaled gpu frequency for the ring.
v3: s/max_ring_freq/min_ring_freq/ as that is what it is
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
[danvet: Add space checkpatch complained about.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index e0fc070..077d40f 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1210,6 +1210,9 @@
#define MCHBAR_MIRROR_BASE_SNB 0x140000
+/* Memory controller frequency in MCHBAR for Haswell (possible SNB+) */
+#define DCLK 0x5e04
+
/** 915-945 and GM965 MCH register controlling DRAM channel access */
#define DCC 0x10200
#define DCC_ADDRESSING_MODE_SINGLE_CHANNEL (0 << 0)
@@ -4390,6 +4393,7 @@
#define GEN6_DECODE_RC6_VID(vids) (((vids) * 5) + 245)
#define GEN6_PCODE_DATA 0x138128
#define GEN6_PCODE_FREQ_IA_RATIO_SHIFT 8
+#define GEN6_PCODE_FREQ_RING_RATIO_SHIFT 16
#define VLV_IOSF_DOORBELL_REQ 0x182100
#define IOSF_DEVFN_SHIFT 24