[Intel-gfx] [PATCH 3/3] drm/i915: Add module parameter to remove RCS engine

[Stuart Summers]

In some debug scenarios, it might be interesting to load
a platform without support for the render command streamer.
Add a module parameter to allow this platform configuration.

Signed-off-by: Stuart Summers <stuart.summers at intel.com>
---
 drivers/gpu/drm/i915/i915_params.c       | 3 +++
 drivers/gpu/drm/i915/i915_params.h       | 3 ++-
 drivers/gpu/drm/i915/intel_device_info.c | 3 +++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 296452f9efe4..9c5115f0e0b1 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -178,6 +178,9 @@ i915_param_named(enable_gvt, bool, 0400,
 	"Enable support for Intel GVT-g graphics virtualization host support(default:false)");
 #endif
 
+i915_param_named_unsafe(enable_rcs, bool, 0400,
+	"Enable the render command streamer. (default: true)");
+
 static __always_inline void _print_param(struct drm_printer *p,
 					 const char *name,
 					 const char *type,
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index d29ade3b7de6..1f07ad5973df 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -77,7 +77,8 @@ struct drm_printer;
 	param(bool, verbose_state_checks, true) \
 	param(bool, nuclear_pageflip, false) \
 	param(bool, enable_dp_mst, true) \
-	param(bool, enable_gvt, false)
+	param(bool, enable_gvt, false) \
+	param(bool, enable_rcs, true)
 
 #define MEMBER(T, member, ...) T member;
 struct i915_params {
diff --git a/drivers/gpu/drm/i915/intel_device_info.c b/drivers/gpu/drm/i915/intel_device_info.c
index f99c9fd497b2..2a80b0d61155 100644
--- a/drivers/gpu/drm/i915/intel_device_info.c
+++ b/drivers/gpu/drm/i915/intel_device_info.c
@@ -1042,4 +1042,7 @@ void intel_device_info_init_mmio(struct drm_i915_private *dev_priv)
 	DRM_DEBUG_DRIVER("vebox enable: %04x, instances: %04lx\n",
 			 vebox_mask, VEBOX_MASK(dev_priv));
 	GEM_BUG_ON(vebox_mask != VEBOX_MASK(dev_priv));
+
+	if (!i915_modparams.enable_rcs)
+		info->engine_mask &= ~BIT(RCS0);
 }
-- 
2.22.0