[Intel-gfx] [PATCH] drm/i915: Initialize HWS page address after GPU reset

[Arun Siluvery]

After GPU reset, HW is losing the address of HWS page in the register.
The page itself is valid except that HW is not aware of its location.

[   64.368623] [drm:gen8_init_common_ring [i915]] *ERROR* HWS Page address = 0x00000000
[   64.368655] [drm:gen8_init_common_ring [i915]] *ERROR* HWS Page address = 0x00000000
[   64.368681] [drm:gen8_init_common_ring [i915]] *ERROR* HWS Page address = 0x00000000
[   64.368704] [drm:gen8_init_common_ring [i915]] *ERROR* HWS Page address = 0x00000000

This patch reloads this value into the register during ring init.

Change-Id: Ibdd1e4645921b4deb02dfc8d0d8e6ba993ce7371
Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 0413b8f..73033f5 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1085,6 +1085,12 @@ static int gen8_init_common_ring(struct intel_engine_cs *ring)
 	I915_WRITE_IMR(ring, ~(ring->irq_enable_mask | ring->irq_keep_mask));
 	I915_WRITE(RING_HWSTAM(ring->mmio_base), 0xffffffff);
 
+	if (ring->status_page.obj) {
+		I915_WRITE(RING_HWS_PGA(ring->mmio_base),
+			   (u32)ring->status_page.gfx_addr);
+		POSTING_READ(RING_HWS_PGA(ring->mmio_base));
+	}
+
 	I915_WRITE(RING_MODE_GEN7(ring),
 		   _MASKED_BIT_DISABLE(GFX_REPLAY_MODE) |
 		   _MASKED_BIT_ENABLE(GFX_RUN_LIST_ENABLE));
-- 
2.3.0