From: Akash Goel <akash.g...@intel.com>
Ring frequency table programming changes for SKL. No need for a
floor on ring frequency, as the issue of performance impact with
ring running below DDR frequency, is believed to be fixed on SKL
v2: Removed the check for avoiding ring frequency programming for BXT (Rodrigo)
Issue: VIZ-5144
Signed-off-by: Akash Goel <akash.g...@intel.com>
---
drivers/gpu/drm/i915/intel_pm.c | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 1d14cce2..65938ea 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4622,6 +4622,7 @@ static void __gen6_update_ring_freq(struct drm_device
*dev)
int min_freq = 15;
unsigned int gpu_freq;
unsigned int max_ia_freq, min_ring_freq;
+ unsigned int max_gpu_freq, min_gpu_freq;
int scaling_factor = 180;
struct cpufreq_policy *policy;
@@ -4646,17 +4647,31 @@ static void __gen6_update_ring_freq(struct drm_device
*dev)
/* convert DDR frequency from units of 266.6MHz to bandwidth */
min_ring_freq = mult_frac(min_ring_freq, 8, 3);
+ if (IS_SKYLAKE(dev)) {
+ /* Convert GT frequency to 50 HZ units */
+ min_gpu_freq = dev_priv->rps.min_freq / GEN9_FREQ_SCALER;
+ max_gpu_freq = dev_priv->rps.max_freq / GEN9_FREQ_SCALER;
+ } else {
+ min_gpu_freq = dev_priv->rps.min_freq;
+ max_gpu_freq = dev_priv->rps.max_freq;
+ }
+
/*
* For each potential GPU frequency, load a ring frequency we'd like
* to use for memory access. We do this by specifying the IA frequency
* the PCU should use as a reference to determine the ring frequency.
*/
- for (gpu_freq = dev_priv->rps.max_freq; gpu_freq >=
dev_priv->rps.min_freq;
- gpu_freq--) {
- int diff = dev_priv->rps.max_freq - gpu_freq;
+ for (gpu_freq = max_gpu_freq; gpu_freq >= min_gpu_freq; gpu_freq--) {
+ int diff = max_gpu_freq - gpu_freq;
unsigned int ia_freq = 0, ring_freq = 0;
- if (INTEL_INFO(dev)->gen >= 8) {
+ if (IS_SKYLAKE(dev)) {
+ /*
+ * ring_freq = 2 * GT. ring_freq is in 100MHz units
+ * No floor required for ring frequency on SKL.
+ */
+ ring_freq = gpu_freq;
+ } else if (INTEL_INFO(dev)->gen >= 8) {
/* max(2 * GT, DDR). NB: GT is 50MHz units */
ring_freq = max(min_ring_freq, gpu_freq);
} else if (IS_HASWELL(dev)) {
--
1.9.2
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