drm/i915: Disable MI_STORE_DATA_IMM for i915g/i915gm

The early gen3 machines (i915g/Grantsdale and i915gm/Alviso) share a lot
of characteristics in their MI/GTT blocks with gen2, and in particular
can only use physical addresses in MI_STORE_DATA_IMM. This makes it
incompatible with our usage, so include those two machines in the
blacklist to prevent usage.

v2: Make it easy for gcc and rewrite it as a switch to save some space.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20170906152859.5304-1-chris@chris-wilson.co.uk

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index ae668340620e..23812ec23969 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1378,6 +1378,21 @@ void intel_engines_mark_idle(struct drm_i915_private *i915)
         }
 }
 
+bool intel_engine_can_store_dword(struct intel_engine_cs *engine)
+{
+        switch (INTEL_GEN(engine->i915)) {
+        case 2:
+                return false; /* uses physical not virtual addresses */
+        case 3:
+                /* maybe only uses physical not virtual addresses */
+                return !(IS_I915G(engine->i915) || IS_I915GM(engine->i915));
+        case 6:
+                return engine->class != VIDEO_DECODE_CLASS; /* b0rked */
+        default:
+                return true;
+        }
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
 #include "selftests/mock_engine.c"
 #endif