drm/i915/gen9: Fix PCODE polling during SAGV disabling

According to the previous patch, it's possible atm that we call
intel_do_sagv_disable() only once during the 1ms period and time out if
that call fails. As opposed to this the spec says that we need to keep
retrying this request for a 1ms duration, so let's do this similarly to
the CDCLK change notification request.

v4-5:
- Rebased on the reply_mask, reply change.
v6:
- Remove w/s change. (Lyude)
- Rebased on the timeout_base argument change.

Cc: Lyude <cpaul@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Fixes: 656d1b89e5ff ("drm/i915/skl: Add support for the SAGV, fix underrun hangs")
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Lyude <lyude@redhat.com> (v4)
Link: http://patchwork.freedesktop.org/patch/msgid/1480955258-26311-2-git-send-email-imre.deak@intel.com
(cherry picked from commit b3b8e99984a4eace91bc097e8f8cec71441cae16)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 90e42e094b1359cf089cb7e8bc67a950e537ecaa..1377679ac10954581181ce372c65dab1242626ab 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2964,24 +2964,10 @@ intel_enable_sagv(struct drm_i915_private *dev_priv)
        return 0;
 }
 
-static int
-intel_do_sagv_disable(struct drm_i915_private *dev_priv)
-{
-       int ret;
-       uint32_t temp = GEN9_SAGV_DISABLE;
-
-       ret = sandybridge_pcode_read(dev_priv, GEN9_PCODE_SAGV_CONTROL,
-                                    &temp);
-       if (ret)
-               return ret;
-       else
-               return temp & GEN9_SAGV_IS_DISABLED;
-}
-
 int
 intel_disable_sagv(struct drm_i915_private *dev_priv)
 {
-       int ret, result;
+       int ret;
 
        if (!intel_has_sagv(dev_priv))
                return 0;
@@ -2993,25 +2979,23 @@ intel_disable_sagv(struct drm_i915_private *dev_priv)
        mutex_lock(&dev_priv->rps.hw_lock);
 
        /* bspec says to keep retrying for at least 1 ms */
-       ret = wait_for(result = intel_do_sagv_disable(dev_priv), 1);
+       ret = skl_pcode_request(dev_priv, GEN9_PCODE_SAGV_CONTROL,
+                               GEN9_SAGV_DISABLE,
+                               GEN9_SAGV_IS_DISABLED, GEN9_SAGV_IS_DISABLED,
+                               1);
        mutex_unlock(&dev_priv->rps.hw_lock);
 
-       if (ret == -ETIMEDOUT) {
-               DRM_ERROR("Request to disable SAGV timed out\n");
-               return -ETIMEDOUT;
-       }
-
        /*
         * Some skl systems, pre-release machines in particular,
         * don't actually have an SAGV.
         */
-       if (IS_SKYLAKE(dev_priv) && result == -ENXIO) {
+       if (IS_SKYLAKE(dev_priv) && ret == -ENXIO) {
                DRM_DEBUG_DRIVER("No SAGV found on system, ignoring\n");
                dev_priv->sagv_status = I915_SAGV_NOT_CONTROLLED;
                return 0;
-       } else if (result < 0) {
-               DRM_ERROR("Failed to disable the SAGV\n");
-               return result;
+       } else if (ret < 0) {
+               DRM_ERROR("Failed to disable the SAGV (%d)\n", ret);
+               return ret;
        }
 
        dev_priv->sagv_status = I915_SAGV_DISABLED;