drm/i915: Track all held rpm wakerefs
Everytime we take a wakeref, record the stack trace of where it was
taken; clearing the set if we ever drop back to no owners. For debugging
a rpm leak, we can look at all the current wakerefs and check if they
have a matching rpm_put.
v2: Use skip=0 for unwinding the stack as it appears our noinline
function doesn't appear on the stack (nor does save_stack_trace itself!)
v3: Allow rpm->debug_count to disappear between inspections and so
avoid calling krealloc(0) as that may return a ZERO_PTR not NULL! (Mika)
v4: Show who last acquire/released the runtime pm
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Tested-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190114142129.24398-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
index 9e36ffb..ad4d711 100644
--- a/drivers/gpu/drm/i915/Kconfig.debug
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -21,11 +21,11 @@
select DEBUG_FS
select PREEMPT_COUNT
select I2C_CHARDEV
+ select STACKDEPOT
select DRM_DP_AUX_CHARDEV
select X86_MSR # used by igt/pm_rpm
select DRM_VGEM # used by igt/prime_vgem (dmabuf interop checks)
select DRM_DEBUG_MM if DRM=y
- select STACKDEPOT if DRM=y # for DRM_DEBUG_MM
select DRM_DEBUG_SELFTEST
select SW_SYNC # signaling validation framework (igt/syncobj*)
select DRM_I915_SW_FENCE_DEBUG_OBJECTS
@@ -173,6 +173,7 @@
bool "Enable extra state checking for runtime PM"
depends on DRM_I915
default n
+ select STACKDEPOT
help
Choose this option to turn on extra state checking for the
runtime PM functionality. This may introduce overhead during