On Thu, Apr 21, 2016 at 12:33:41PM +0530, akash.g...@intel.com wrote:
> From: Akash Goel <akash.g...@intel.com>
>
> As a part of WaGsvDisableTurbo, Driver makes an early exit from the
> Gen9 Turbo enabling function, so doesn't program the Turbo Control register.
> But BIOS could leave the Hw Turbo as enabled, so need to explicitly clear
> out the Control register just to avoid inconsitency with debugfs
> interface, which will show Turbo as enabled only and that is not expected
> after adding the WaGsvDisableTurbo. Apart from this there is no problem
> even if the Turbo is left enabled in the Control register, as the Up/Down
> interrupts would remain masked.
>
> Signed-off-by: Akash Goel <akash.g...@intel.com>
> ---
> drivers/gpu/drm/i915/intel_pm.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index b7c2186..41d5586 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4804,6 +4804,16 @@ static void gen9_enable_rps(struct drm_device *dev)
>
> /* WaGsvDisableTurbo: Workaround to disable turbo on BXT A* */
> if (IS_BXT_REVID(dev, 0, BXT_REVID_A1)) {
> + /*
> + * BIOS could leave the Hw Turbo enabled, so need to explicitly
> + * clear out the Control register just to avoid inconsitency
> + * with debugfs interface, which will show Turbo as enabled
> + * only and that is not expected by the User after adding the
> + * WaGsvDisableTurbo. Apart from this there is no problem even
> + * if the Turbo is left enabled in the Control register, as the
> + * Up/Down interrupts would remain masked.
> + */
> + I915_WRITE(GEN6_RP_CONTROL, 0);
First question. Do we not want to sanitize bios state for everybody
during init? That is the usual procedure.
None of the *_disable_rps() actually clear GEN6_RP_CONTROL. They should
according to the rationale above. And then this should be a call to
gen9_disable_rps().
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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