[Intel-gfx] [PATCH] drm/i915: reinit status page registers after gpu reset

[Daniel Vetter]

This fixes gpu reset on my gm45 - without this patch the bsd thing is
forever stuck since the seqno updates never reach the status page.

Tbh I have no idea how this ever worked without rewriting the hws
registers after a gpu reset.

To satisfy my OCD also give the functions a bit more consistent names:
- Use status_page everywhere, also for the physical addressed one.
- Use init for the allocation part and setup for the register setup
  part consistently.

Long term I'd really like to share the hw init parts completely
between gpu reset, resume and driver load, i.e. to call
i915_gem_init_hw instead of the individual pieces we might need.

v2: Add the missing paragraph to the commit message about what bug
exactly this patch here fixes.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=65495
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index e51ab55..18ca76e 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -379,6 +379,17 @@ u32 intel_ring_get_active_head(struct intel_ring_buffer *ring)
 	return I915_READ(acthd_reg);
 }
 
+static void ring_setup_phys_status_page(struct intel_ring_buffer *ring)
+{
+	struct drm_i915_private *dev_priv = ring->dev->dev_private;
+	u32 addr;
+
+	addr = dev_priv->status_page_dmah->busaddr;
+	if (INTEL_INFO(ring->dev)->gen >= 4)
+		addr |= (dev_priv->status_page_dmah->busaddr >> 28) & 0xf0;
+	I915_WRITE(HWS_PGA, addr);
+}
+
 static int init_ring_common(struct intel_ring_buffer *ring)
 {
 	struct drm_device *dev = ring->dev;
@@ -390,6 +401,11 @@ static int init_ring_common(struct intel_ring_buffer *ring)
 	if (HAS_FORCE_WAKE(dev))
 		gen6_gt_force_wake_get(dev_priv);
 
+	if (I915_NEED_GFX_HWS(dev))
+		intel_ring_setup_status_page(ring);
+	else
+		ring_setup_phys_status_page(ring);
+
 	/* Stop the ring if it's running. */
 	I915_WRITE_CTL(ring, 0);
 	I915_WRITE_HEAD(ring, 0);
@@ -1223,7 +1239,6 @@ static int init_status_page(struct intel_ring_buffer *ring)
 	ring->status_page.obj = obj;
 	memset(ring->status_page.page_addr, 0, PAGE_SIZE);
 
-	intel_ring_setup_status_page(ring);
 	DRM_DEBUG_DRIVER("%s hws offset: 0x%08x\n",
 			ring->name, ring->status_page.gfx_addr);
 
@@ -1237,10 +1252,9 @@ err:
 	return ret;
 }
 
-static int init_phys_hws_pga(struct intel_ring_buffer *ring)
+static int init_phys_status_page(struct intel_ring_buffer *ring)
 {
 	struct drm_i915_private *dev_priv = ring->dev->dev_private;
-	u32 addr;
 
 	if (!dev_priv->status_page_dmah) {
 		dev_priv->status_page_dmah =
@@ -1249,11 +1263,6 @@ static int init_phys_hws_pga(struct intel_ring_buffer *ring)
 			return -ENOMEM;
 	}
 
-	addr = dev_priv->status_page_dmah->busaddr;
-	if (INTEL_INFO(ring->dev)->gen >= 4)
-		addr |= (dev_priv->status_page_dmah->busaddr >> 28) & 0xf0;
-	I915_WRITE(HWS_PGA, addr);
-
 	ring->status_page.page_addr = dev_priv->status_page_dmah->vaddr;
 	memset(ring->status_page.page_addr, 0, PAGE_SIZE);
 
@@ -1281,7 +1290,7 @@ static int intel_init_ring_buffer(struct drm_device *dev,
 			return ret;
 	} else {
 		BUG_ON(ring->id != RCS);
-		ret = init_phys_hws_pga(ring);
+		ret = init_phys_status_page(ring);
 		if (ret)
 			return ret;
 	}
@@ -1893,7 +1902,7 @@ int intel_render_ring_init_dri(struct drm_device *dev, u64 start, u32 size)
 	}
 
 	if (!I915_NEED_GFX_HWS(dev)) {
-		ret = init_phys_hws_pga(ring);
+		ret = init_phys_status_page(ring);
 		if (ret)
 			return ret;
 	}
-- 
1.8.3.1