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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - [BYT] Offscreen tests performance drops to <1/3 due to power management"
href="https://bugs.freedesktop.org/show_bug.cgi?id=102336#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - [BYT] Offscreen tests performance drops to <1/3 due to power management"
href="https://bugs.freedesktop.org/show_bug.cgi?id=102336">bug 102336</a>
from <span class="vcard"><a class="email" href="mailto:chris@chris-wilson.co.uk" title="Chris Wilson <chris@chris-wilson.co.uk>"> <span class="fn">Chris Wilson</span></a>
</span></b>
<pre>Maxing out the GPU (at least GAM) results in 50% c0 activity. I'm guessing out
cdlck is incorrect, or slightly different to the c0 cycles:
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 32c62442c9d8..4b36ed2290b9 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1076,7 +1076,7 @@ static u32 vlv_wa_c0_ei(struct drm_i915_private
*dev_priv, u32 pm_iir)
time = ktime_us_delta(now.ktime, prev->ktime);
- time *= dev_priv->czclk_freq;
+ time *= dev_priv->czclk_freq / 2;
/* Workload can be split between render + media,
* e.g. SwapBuffers being blitted in X after being rendered in</pre>
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