drm/i915: Allow disabling error capture
We currently capture the GPU state after we detect a hang. This is vital
for us to both triage and debug hangs in the wild (post-mortem
debugging). However, it comes at the cost of running some potentially
dangerous code (since it has to make very few assumption about the state
of the driver) that is quite resource intensive.
This patch introduces both a method to disable error capture at runtime
(for users who hit bugs at runtime and need a workaround) and to disable
error capture at compiletime (for realtime users who want to minimise
any possible latency, and never require error capture, saving ~30k of
code). The cost is that we now have to be wary of (and test!) a kconfig
flag and a module parameter. The effect of the module parameter is easy
to verify through code inspection and runtime testing, but a kconfig flag
needs regular compile checking.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch
Link: http://patchwork.freedesktop.org/patch/msgid/20161012090522.367-2-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 4553a53..380590b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3544,6 +3544,8 @@
#endif
/* i915_gpu_error.c */
+#if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
+
__printf(2, 3)
void i915_error_printf(struct drm_i915_error_state_buf *e, const char *f, ...);
int i915_error_state_to_str(struct drm_i915_error_state_buf *estr,
@@ -3564,6 +3566,20 @@
void i915_error_state_put(struct i915_error_state_file_priv *error_priv);
void i915_destroy_error_state(struct drm_device *dev);
+#else
+
+static inline void i915_capture_error_state(struct drm_i915_private *dev_priv,
+ u32 engine_mask,
+ const char *error_msg)
+{
+}
+
+static inline void i915_destroy_error_state(struct drm_device *dev)
+{
+}
+
+#endif
+
const char *i915_cache_level_str(struct drm_i915_private *i915, int type);
/* i915_cmd_parser.c */