[Intel-gfx] [PATCH v2 1/2] drm/i915/tgl: add GEN12_MAX_CONTEXT_HW_ID

[Daniele Ceraolo Spurio]

Like Gen11, Gen12 has 11 available bits for the ctx id field. However,
the last value (0x7FF) is reserved to indicate engine idle, so we
need to reduce the maximum number of contexts by 1 compared to Gen11.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 4 +++-
 drivers/gpu/drm/i915/i915_drv.h             | 2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 64f7a533e886..5c474f38bac6 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -172,7 +172,9 @@ static inline int new_hw_id(struct drm_i915_private *i915, gfp_t gfp)
 
 	lockdep_assert_held(&i915->contexts.mutex);
 
-	if (INTEL_GEN(i915) >= 11)
+	if (INTEL_GEN(i915) >= 12)
+		max = GEN12_MAX_CONTEXT_HW_ID;
+	else if (INTEL_GEN(i915) >= 11)
 		max = GEN11_MAX_CONTEXT_HW_ID;
 	else if (USES_GUC_SUBMISSION(i915))
 		/*
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 8931dd847bb5..be5995c60f73 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1581,6 +1581,8 @@ struct drm_i915_private {
 #define MAX_CONTEXT_HW_ID (1<<21) /* exclusive */
 #define MAX_GUC_CONTEXT_HW_ID (1 << 20) /* exclusive */
 #define GEN11_MAX_CONTEXT_HW_ID (1<<11) /* exclusive */
+/* in Gen12 ID 0x7FF is reserved to indicate idle */
+#define GEN12_MAX_CONTEXT_HW_ID	(GEN11_MAX_CONTEXT_HW_ID - 1)
 		struct list_head hw_id_list;
 	} contexts;
 
-- 
2.22.0