[PATCH v2 2/2] drm/i915/dg2: Add debugfs to control global preemption setting

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 

From: Akeem G Abodunrin <akeem.g.abodunrin@xxxxxxxxx>

Since DG2 and beyond only support global preemption enable/disable (see
Wa_14015141709), userspace no longer has a way to control preemption on
a per-context basis.  Preemption is globally enabled by default, but the
UMD teams have requested that we provide a debugfs interface that can be
used to query and adjust the system-wide preemption setting for
development and bug reporting purposes.

v2 (MattR):
 - Split debugfs out into a separate patch.  (Jani)
 - Add the hardware update/query as facilities in intel_gt.c and just
   call them from the debugfs code.  (Jani)
 - Add register to GuC's save/restore list so that the value will
   persist across resets.  (Tvrtko)
 - Place under per-GT debugfs rather than i915 debugfs.  (MattR)
 - Only register debugfs entries on platforms subject to Wa_14015141709,
   and only on platforms that have an RCS engine.  (MattR/Tvrtko)

Cc: Matt Roper <matthew.d.roper@xxxxxxxxx>
Cc: Prathap Kumar Valsan <prathap.kumar.valsan@xxxxxxxxx>
Cc: John Harrison <john.c.harrison@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@xxxxxxxxx>
Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gt/intel_gt.c         | 50 ++++++++++++++++++++++
 drivers/gpu/drm/i915/gt/intel_gt.h         |  3 ++
 drivers/gpu/drm/i915/gt/intel_gt_debugfs.c | 31 ++++++++++++++
 drivers/gpu/drm/i915/gt/intel_gt_regs.h    |  3 ++
 drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c |  7 +++
 5 files changed, 94 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index 8a2483ccbfb9..90bdebd8d267 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -1045,3 +1045,53 @@ void intel_gt_invalidate_tlbs(struct intel_gt *gt)
 	intel_uncore_forcewake_put_delayed(uncore, FORCEWAKE_ALL);
 	mutex_unlock(&gt->tlb_invalidate_lock);
 }
+
+/**
+ * intel_gt_get_global_preemption - return whether the global preemption
+ *     setting is enabled in hardware
+ * @gt: GT structure
+ *
+ * Returns the hardware's global 'preemption enabled' setting.  Only relevant
+ * on newer platforms that lack per-context preemption control (and only on
+ * GTs that have a render engine).
+ *
+ * Returns 1 if preemption is enabled, 0 if disabled.
+ */
+u64 intel_gt_get_global_preemption(struct intel_gt *gt)
+{
+	intel_wakeref_t wakeref;
+	u32 val;
+
+	drm_WARN_ON(&gt->i915->drm, GRAPHICS_VER_FULL(gt->i915) < IP_VER(12, 55));
+	drm_WARN_ON(&gt->i915->drm, RCS_MASK(gt) == 0);
+
+	with_intel_runtime_pm(&gt->i915->runtime_pm, wakeref)
+		val = intel_uncore_read(gt->uncore, GEN12_VFG_PREEMPTION_CHICKEN);
+
+	return !(val & GEN12_VFG_PREEMPT_CHICKEN_DISABLE);
+}
+
+/**
+ * intel_gt_set_global_preemption - adjust global preemption enabled setting
+ * @gt: GT structure
+ * @val: desired preemption setting
+ *
+ * Enables global preemption if @val is non-zero, otherwise disables it.  Only
+ * relevant on newer platforms that lack per-context preemption control (and
+ * only on GTs that have a render engine).
+ *
+ * Returns 1 if preemption is enabled, 0 if disabled.
+ */
+void intel_gt_set_global_preemption(struct intel_gt *gt, u64 val)
+{
+	intel_wakeref_t wakeref;
+	u32 tmp = val ?
+		_MASKED_BIT_DISABLE(GEN12_VFG_PREEMPT_CHICKEN_DISABLE) :
+		_MASKED_BIT_ENABLE(GEN12_VFG_PREEMPT_CHICKEN_DISABLE);
+
+	drm_WARN_ON(&gt->i915->drm, GRAPHICS_VER_FULL(gt->i915) < IP_VER(12, 55));
+	drm_WARN_ON(&gt->i915->drm, RCS_MASK(gt) == 0);
+
+	with_intel_runtime_pm(&gt->i915->runtime_pm, wakeref)
+		intel_uncore_write(gt->uncore, GEN12_VFG_PREEMPTION_CHICKEN, tmp);
+}
diff --git a/drivers/gpu/drm/i915/gt/intel_gt.h b/drivers/gpu/drm/i915/gt/intel_gt.h
index 0f571c8ee22b..63a599a1bf6d 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt.h
@@ -94,4 +94,7 @@ void intel_gt_watchdog_work(struct work_struct *work);
 
 void intel_gt_invalidate_tlbs(struct intel_gt *gt);
 
+u64 intel_gt_get_global_preemption(struct intel_gt *gt);
+void intel_gt_set_global_preemption(struct intel_gt *gt, u64 val);
+
 #endif /* __INTEL_GT_H__ */
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_debugfs.c b/drivers/gpu/drm/i915/gt/intel_gt_debugfs.c
index f103664b71d4..d851e3f80877 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_debugfs.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_debugfs.c
@@ -6,6 +6,7 @@
 #include <linux/debugfs.h>
 
 #include "i915_drv.h"
+#include "intel_gt.h"
 #include "intel_gt_debugfs.h"
 #include "intel_gt_engines_debugfs.h"
 #include "intel_gt_pm_debugfs.h"
@@ -57,13 +58,43 @@ static int __intel_gt_debugfs_reset_store(void *data, u64 val)
 DEFINE_SIMPLE_ATTRIBUTE(reset_fops, __intel_gt_debugfs_reset_show,
 			__intel_gt_debugfs_reset_store, "%llu\n");
 
+static int i915_global_preemption_enabled_get(void *data, u64 *val)
+{
+	*val = intel_gt_get_global_preemption((struct intel_gt *)data);
+
+	return 0;
+}
+
+static int i915_global_preemption_enabled_set(void *data, u64 val)
+{
+	intel_gt_set_global_preemption((struct intel_gt *)data, val);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(i915_global_preemption_enabled_fops,
+			i915_global_preemption_enabled_get,
+			i915_global_preemption_enabled_set,
+			"%llu\n");
+
 static void gt_debugfs_register(struct intel_gt *gt, struct dentry *root)
 {
 	static const struct intel_gt_debugfs_file files[] = {
 		{ "reset", &reset_fops, NULL },
 	};
+	static const struct  intel_gt_debugfs_file preempt_files[] = {
+		{ "preemption_enabled", &i915_global_preemption_enabled_fops }
+	};
 
 	intel_gt_debugfs_register_files(root, files, ARRAY_SIZE(files), gt);
+
+	/*
+	 * Global preemption control only applies to DG2 and beyond
+	 * (Wa_14015141709) and only to GTs with an RCS.
+	 */
+	if (GRAPHICS_VER_FULL(gt->i915) >= IP_VER(12, 55) && RCS_MASK(gt))
+		intel_gt_debugfs_register_files(root, preempt_files,
+						ARRAY_SIZE(preempt_files), gt);
 }
 
 void intel_gt_debugfs_register(struct intel_gt *gt)
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
index 19cd34f24263..21ede1887b9f 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
@@ -468,6 +468,9 @@
 #define VF_PREEMPTION				_MMIO(0x83a4)
 #define   PREEMPTION_VERTEX_COUNT		REG_GENMASK(15, 0)
 
+#define GEN12_VFG_PREEMPTION_CHICKEN		_MMIO(0x83b4)
+#define   GEN12_VFG_PREEMPT_CHICKEN_DISABLE	REG_BIT(8)
+
 #define GEN8_RC6_CTX_INFO			_MMIO(0x8504)
 
 #define GEN12_SQCM				_MMIO(0x8724)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
index acc4a3766dc1..7e008382ab03 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ads.c
@@ -352,6 +352,13 @@ static int guc_mmio_regset_init(struct temp_regset *regset,
 	for (i = 0; i < GEN9_LNCFCMOCS_REG_COUNT; i++)
 		ret |= GUC_MMIO_REG_ADD(regset, GEN9_LNCFCMOCS(i), false);
 
+	/*
+	 * VFG_PREEMPTION_CHICKEN can be controlled via debugfs; ensure
+	 * the setting sticks across resets
+	 */
+	if (engine->flags & I915_ENGINE_FIRST_RENDER_COMPUTE)
+		ret |= GUC_MMIO_REG_ADD(regset, GEN12_VFG_PREEMPTION_CHICKEN, true);
+
 	return ret ? -1 : 0;
 }
 
-- 
2.34.1
[Index of Archives]     [Linux DRI Users]     [Linux Intel Graphics]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux