drm/i915: Restore very early GPU reset

In commit d03b224f4252 ("drm/i915/gt: Apply sanitiization just before
resume") the GT sanitization was pulled into the resume path as we need
to know the backend in order to do a full reset prior to resume.
However, it is still imperative that we scrub existing GPU state before
clobbering in our early setup, so restore a minimal GPU reset at the
start of our init sequence.

Fixes: d03b224f4252 ("drm/i915/gt: Apply sanitiization just before resume")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191228111255.3086901-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 5e6e86c..fde5487 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -469,6 +469,12 @@ static void vlv_free_s0ix_state(struct drm_i915_private *i915)
        i915->vlv_s0ix_state = NULL;
 }
 
+static void sanitize_gpu(struct drm_i915_private *i915)
+{
+       if (!INTEL_INFO(i915)->gpu_reset_clobbers_display)
+               __intel_gt_reset(&i915->gt, ALL_ENGINES);
+}
+
 /**
  * i915_driver_early_probe - setup state not requiring device access
  * @dev_priv: device private
@@ -602,6 +608,9 @@ static int i915_driver_mmio_probe(struct drm_i915_private *dev_priv)
        if (ret)
                goto err_uncore;
 
+       /* As early as possible, scrub existing GPU state before clobbering */
+       sanitize_gpu(dev_priv);
+
        return 0;
 
 err_uncore:
@@ -1817,6 +1826,8 @@ static int i915_drm_resume(struct drm_device *dev)
 
        disable_rpm_wakeref_asserts(&dev_priv->runtime_pm);
 
+       sanitize_gpu(dev_priv);
+
        ret = i915_ggtt_enable_hw(dev_priv);
        if (ret)
                DRM_ERROR("failed to re-enable GGTT\n");