Otherwise using any atomic memory operation will lock up the GPU due
to a Haswell hardware bug. This patch also defines a new DRM param so
userspace knows that atomics can be used safely.
Signed-off-by: Francisco Jerez <currojerez@xxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_dma.c | 3 +++
drivers/gpu/drm/i915/i915_reg.h | 7 +++++++
drivers/gpu/drm/i915/intel_pm.c | 6 ++++++
include/uapi/drm/i915_drm.h | 1 +
4 files changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index c27a210..e4fcb3d 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1003,6 +1003,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
case I915_PARAM_HAS_EXEC_HANDLE_LUT:
value = 1;
break;
+ case I915_PARAM_HAS_ATOMICS:
+ value = 1;
+ break;
default:
DRM_DEBUG("Unknown parameter %d\n", param->param);
return -EINVAL;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index c159e1a..611a863 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3881,6 +3881,9 @@
#define GEN7_SQ_CHICKEN_MBCUNIT_CONFIG 0x9030
#define GEN7_SQ_CHICKEN_MBCUNIT_SQINTMOB (1<<11)
+#define HSW_SCRATCH1 0xb038
+#define HSW_SCRATCH1_L3_DATA_ATOMICS_DISABLE (1<<27)
+
#define HSW_FUSE_STRAP 0x42014
#define HSW_CDCLK_LIMIT (1 << 24)
@@ -4728,6 +4731,10 @@
#define GEN7_ROW_CHICKEN2_GT2 0xf4f4
#define DOP_CLOCK_GATING_DISABLE (1<<0)
+#define HSW_ROW_CHICKEN3 0xe49c
+#define HSW_ROW_CHICKEN3_L3_GLOBAL_ATOMICS_MASK (1 << 22)
+#define HSW_ROW_CHICKEN3_L3_GLOBAL_ATOMICS_DISABLE (1 << 6)
+
#define G4X_AUD_VID_DID (dev_priv->info->display_mmio_offset + 0x62020)
#define INTEL_AUDIO_DEVCL 0x808629FB
#define INTEL_AUDIO_DEVBLC 0x80862801
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index dd176b7..47f2b2f 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4955,6 +4955,12 @@ static void haswell_init_clock_gating(struct drm_device *dev)
I915_WRITE(GEN7_L3_CHICKEN_MODE_REGISTER,
GEN7_WA_L3_CHICKEN_MODE);
+ /* L3 caching of data atomics doesn't work -- disable it. */
+ I915_WRITE(HSW_SCRATCH1, HSW_SCRATCH1_L3_DATA_ATOMICS_DISABLE);
+ I915_WRITE(HSW_ROW_CHICKEN3,
+ HSW_ROW_CHICKEN3_L3_GLOBAL_ATOMICS_MASK |
+ HSW_ROW_CHICKEN3_L3_GLOBAL_ATOMICS_DISABLE);
+
/* This is required by WaCatErrorRejectionIssue:hsw */
I915_WRITE(GEN7_SQ_CHICKEN_MBCUNIT_CONFIG,
I915_READ(GEN7_SQ_CHICKEN_MBCUNIT_CONFIG) |
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 55bb572..fe0f52e 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -335,6 +335,7 @@ typedef struct drm_i915_irq_wait {
#define I915_PARAM_HAS_EXEC_NO_RELOC 25
#define I915_PARAM_HAS_EXEC_HANDLE_LUT 26
#define I915_PARAM_HAS_WT 27
+#define I915_PARAM_HAS_ATOMICS 28
typedef struct drm_i915_getparam {
int param;
--
1.8.3.4
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