[Intel-gfx] [PATCH 21/39] drm/i915: Added a module parameter for allowing scheduler overrides

[John.C.Harrison at Intel.com]

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

It can be useful to be able to disable certain features (e.g. the entire
scheduler) via a module parameter for debugging purposes. A parameter has the
advantage of not being a compile time switch but without implying that it can be
changed dynamically at runtime.

Change-Id: I92f4c832be88f5b34b49b90d6a9903fac68f7004
For: VIZ-1587
Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h       | 1 +
 drivers/gpu/drm/i915/i915_params.c    | 4 ++++
 drivers/gpu/drm/i915/i915_scheduler.c | 5 ++++-
 drivers/gpu/drm/i915/i915_scheduler.h | 5 +++++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 5ed600c..5b893a6 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2717,6 +2717,7 @@ struct i915_params {
 	bool verbose_state_checks;
 	bool nuclear_pageflip;
 	int edp_vswing;
+	int scheduler_override;
 };
 extern struct i915_params i915 __read_mostly;
 
diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index ba7274a..be2e16c 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -54,6 +54,7 @@ struct i915_params i915 __read_mostly = {
 	.edp_vswing = 0,
 	.enable_guc_submission = true,
 	.guc_log_level = -1,
+	.scheduler_override = 1,
 };
 
 module_param_named(modeset, i915.modeset, int, 0400);
@@ -191,3 +192,6 @@ 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(scheduler_override, i915.scheduler_override, int, 0600);
+MODULE_PARM_DESC(scheduler_override, "Scheduler override mask (0 = none, 1 = direct submission [default])");
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index 232f48a..f51676b 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -44,6 +44,9 @@ bool i915_scheduler_is_enabled(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
+	if (i915.scheduler_override & i915_so_direct_submit)
+		return false;
+
 	return dev_priv->scheduler != NULL;
 }
 
@@ -90,7 +93,7 @@ int i915_scheduler_queue_execbuffer(struct i915_scheduler_queue_entry *qe)
 
 	BUG_ON(!scheduler);
 
-	if (1/*i915.scheduler_override & i915_so_direct_submit*/) {
+	if (i915.scheduler_override & i915_so_direct_submit) {
 		int ret;
 
 		intel_ring_reserved_space_cancel(qe->params.request->ringbuf);
diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
index 29f7248..7e85f80 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.h
+++ b/drivers/gpu/drm/i915/i915_scheduler.h
@@ -83,6 +83,11 @@ enum {
 	i915_sf_submitting          = (1 << 1),
 };
 
+/* Options for 'scheduler_override' module parameter: */
+enum {
+	i915_so_direct_submit       = (1 << 0),
+};
+
 bool        i915_scheduler_is_enabled(struct drm_device *dev);
 int         i915_scheduler_init(struct drm_device *dev);
 int         i915_scheduler_closefile(struct drm_device *dev,
-- 
1.9.1