[PATCH 03/18] drm/i915: Always enable mmio debugging for CI

[Chris Wilson]

The default behaviour is to periodically check for a mmio access error,
and once detected enable mmio access checking. However this is useless
if the error only occurs once.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at intel.com>
---
 drivers/gpu/drm/i915/Kconfig.debug | 12 ++++++++++++
 drivers/gpu/drm/i915/i915_params.h |  8 +++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
index 04b686d2c2d0..53c5f8cd9a1e 100644
--- a/drivers/gpu/drm/i915/Kconfig.debug
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -32,6 +32,7 @@ config DRM_I915_DEBUG
 	select DRM_I915_SW_FENCE_DEBUG_OBJECTS
 	select DRM_I915_SELFTEST
 	select DRM_I915_DEBUG_RUNTIME_PM
+	select DRM_I915_DEBUG_MMIO
         default n
         help
           Choose this option to turn on extra driver debugging that may affect
@@ -41,6 +42,17 @@ config DRM_I915_DEBUG
 
           If in doubt, say "N".
 
+config DRM_I915_DEBUG_MMIO
+        bool "Always insert extra checks around mmio access"
+        default n
+        help
+	  Always enables the extra sanity checks (extra register reads)
+	  around every mmio (register) access that will slow the system down.
+
+          Recommended for driver developers only.
+
+          If in doubt, say "N".
+
 config DRM_I915_DEBUG_GEM
         bool "Insert extra checks into the GEM internals"
         default n
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index 3f14e9881a0d..89018bb2d059 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -33,6 +33,12 @@ struct drm_printer;
 #define ENABLE_GUC_SUBMISSION		BIT(0)
 #define ENABLE_GUC_LOAD_HUC		BIT(1)
 
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_MMIO)
+#define MMIO_DEBUG_DFL -1
+#else
+#define MMIO_DEBUG_DFL 0
+#endif
+
 /*
  * Invoke param, a function-like macro, for each i915 param, with arguments:
  *
@@ -59,7 +65,7 @@ struct drm_printer;
 	param(char *, guc_firmware_path, NULL) \
 	param(char *, huc_firmware_path, NULL) \
 	param(char *, dmc_firmware_path, NULL) \
-	param(int, mmio_debug, 0) \
+	param(int, mmio_debug, MMIO_DEBUG_DFL) \
 	param(int, edp_vswing, 0) \
 	param(int, reset, 2) \
 	param(unsigned int, inject_load_failure, 0) \
-- 
2.20.1