[Intel-gfx] [PATCH v5 21/35] drm/i915: Added a module parameter to allow the scheduler to be disabled

[John.C.Harrison at Intel.com]

From: John Harrison <John.C.Harrison at Intel.com>

It can be useful to be able to disable the GPU scheduler via a module
parameter for debugging purposes.

v5: Converted from a multi-feature 'overrides' mask to a single
'enable' boolean. Further features (e.g. pre-emption) will now be
separate 'enable' booleans added later. [Chris Wilson]

For: VIZ-1587
Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
---
 drivers/gpu/drm/i915/i915_params.c    | 4 ++++
 drivers/gpu/drm/i915/i915_params.h    | 1 +
 drivers/gpu/drm/i915/i915_scheduler.c | 5 ++++-
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index d0eba58..0ef3159 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -57,6 +57,7 @@ struct i915_params i915 __read_mostly = {
 	.edp_vswing = 0,
 	.enable_guc_submission = true,
 	.guc_log_level = -1,
+	.enable_scheduler = 0,
 };
 
 module_param_named(modeset, i915.modeset, int, 0400);
@@ -203,3 +204,6 @@ MODULE_PARM_DESC(enable_guc_submission, "Enable GuC submission (default:false)")
 module_param_named(guc_log_level, i915.guc_log_level, int, 0400);
 MODULE_PARM_DESC(guc_log_level,
 	"GuC firmware logging level (-1:disabled (default), 0-3:enabled)");
+
+module_param_named_unsafe(enable_scheduler, i915.enable_scheduler, int, 0600);
+MODULE_PARM_DESC(enable_scheduler, "Enable scheduler (0 = disable [default], 1 = enable)");
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 5299290..f855c86 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -60,6 +60,7 @@ struct i915_params {
 	bool enable_guc_submission;
 	bool verbose_state_checks;
 	bool nuclear_pageflip;
+	int enable_scheduler;
 };
 
 extern struct i915_params i915 __read_mostly;
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index 4f25bf2..47d7de4 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -34,6 +34,9 @@ bool i915_scheduler_is_enabled(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
+	if (!i915.enable_scheduler)
+		return false;
+
 	return dev_priv->scheduler != NULL;
 }
 
@@ -548,7 +551,7 @@ int i915_scheduler_queue_execbuffer(struct i915_scheduler_queue_entry *qe)
 
 	WARN_ON(!scheduler);
 
-	if (1/*!i915.enable_scheduler*/)
+	if (!i915.enable_scheduler)
 		return i915_scheduler_queue_execbuffer_bypass(qe);
 
 	node = kmalloc(sizeof(*node), GFP_KERNEL);
-- 
1.9.1