Before we can enable 64K pages through the IPS bit, we must first enable
it through MMIO, otherwise the page-walker will simply ignore it.
v2: add comment mentioning that 64K is BDW+
v3: move to more suitable home
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 17 +++++++++++++++++
drivers/gpu/drm/i915/i915_reg.h | 3 +++
2 files changed, 20 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index c989e3d24e37..3115a8ec4376 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1988,6 +1988,23 @@ static void gtt_write_workarounds(struct drm_i915_private *dev_priv)
I915_WRITE(GEN8_L3_LRA_1_GPGPU, GEN9_L3_LRA_1_GPGPU_DEFAULT_VALUE_SKL);
else if (IS_GEN9_LP(dev_priv))
I915_WRITE(GEN8_L3_LRA_1_GPGPU, GEN9_L3_LRA_1_GPGPU_DEFAULT_VALUE_BXT);
+
+ /*
+ * To support 64K PTEs we need to first enable the use of the
+ * Intermediate-Page-Size(IPS) bit of the PDE field via some magical
+ * mmio, otherwise the page-walker will simply ignore the IPS bit. This
+ * shouldn't be needed after GEN10.
+ *
+ * 64K pages were first introduced from BDW+, although technically they
+ * only *work* from gen9+. For pre-BDW we instead have the option for
+ * 32K pages, but we don't currently have any support for it in our
+ * driver.
+ */
+ if (HAS_PAGE_SIZES(dev_priv, I915_GTT_PAGE_SIZE_64K) &&
+ INTEL_GEN(dev_priv) <= 10)
+ I915_WRITE(GEN8_GAMW_ECO_DEV_RW_IA,
+ I915_READ(GEN8_GAMW_ECO_DEV_RW_IA) |
+ GAMW_ECO_ENABLE_64K_IPS_FIELD);
}
int i915_ppgtt_init_hw(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index ee0d4f14ac98..6c2f4c7bf141 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2371,6 +2371,9 @@ enum i915_power_well_id {
#define GEN9_GAMT_ECO_REG_RW_IA _MMIO(0x4ab0)
#define GAMT_ECO_ENABLE_IN_PLACE_DECOMPRESS (1<<18)
+#define GEN8_GAMW_ECO_DEV_RW_IA _MMIO(0x4080)
+#define GAMW_ECO_ENABLE_64K_IPS_FIELD 0xF
+
#define GAMT_CHKN_BIT_REG _MMIO(0x4ab8)
#define GAMT_CHKN_DISABLE_DYNAMIC_CREDIT_SHARING (1<<28)
#define GAMT_CHKN_DISABLE_I2M_CYCLE_ON_WR_PORT (1<<24)
--
2.13.5
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