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-rw-r--r--drivers/gpu/drm/i915/intel_pm.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 85984567afdf..9968c6623020 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5100,7 +5100,17 @@ static int valleyview_rps_rpe_freq(struct drm_i915_private *dev_priv)
static int valleyview_rps_min_freq(struct drm_i915_private *dev_priv)
{
- return vlv_punit_read(dev_priv, PUNIT_REG_GPU_LFM) & 0xff;
+ u32 val;
+
+ val = vlv_punit_read(dev_priv, PUNIT_REG_GPU_LFM) & 0xff;
+ /*
+ * According to the BYT Punit GPU turbo HAS 1.1.6.3 the minimum value
+ * for the minimum frequency in GPLL mode is 0xc1. Contrary to this on
+ * a BYT-M B0 the above register contains 0xbf. Moreover when setting
+ * a frequency Punit will not allow values below 0xc0. Clamp it 0xc0
+ * to make sure it matches what Punit accepts.
+ */
+ return max_t(u32, val, 0xc0);
}
/* Check that the pctx buffer wasn't move under us. */