On 23/05/2017 12:30, Jani Nikula wrote:
On Tue, 23 May 2017, Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx> wrote:
On 23/05/2017 10:56, Jani Nikula wrote:
On Tue, 23 May 2017, Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote:
On Tue, May 23, 2017 at 10:19:31AM +0100, Tvrtko Ursulin wrote:
From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Waiting for engines needs to happen even in the non-debug builds
so it is incorrect to wrap it in a GEM_WARN_ON.
Call it unconditionally and add GEM_WARN so that the debug
warning can still be emitted when things go bad.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Fixes: 25112b64b3d2 ("drm/i915: Wait for all engines to be idle as part of i915_gem_wait_for_idle()")
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Reported-by: Nick Desaulniers <nick.desaulniers@xxxxxxxxx>
Cc: Nick Desaulniers <nick.desaulniers@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem.c | 3 ++-
drivers/gpu/drm/i915/i915_gem.h | 2 ++
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a637cc05cc4a..ecaa21f106c8 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3332,7 +3332,8 @@ static int wait_for_engines(struct drm_i915_private *i915)
enum intel_engine_id id;
for_each_engine(engine, i915, id) {
- if (GEM_WARN_ON(wait_for_engine(engine, 50))) {
+ if (wait_for_engine(engine, 50)) {
+ GEM_WARN(1, "%s wait for idle timeout", engine->name);
Nice touching adding the engine->name
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
i915_gem_set_wedged(i915);
return -EIO;
}
diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index ee54597465b6..cefc6cf96a60 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -30,6 +30,7 @@
#ifdef CONFIG_DRM_I915_DEBUG_GEM
#define GEM_BUG_ON(expr) BUG_ON(expr)
#define GEM_WARN_ON(expr) WARN_ON(expr)
+#define GEM_WARN(condition, format, ...) WARN(condition, format, __VA_ARGS__)
#define GEM_DEBUG_DECL(var) var
#define GEM_DEBUG_EXEC(expr) expr
@@ -38,6 +39,7 @@
#else
#define GEM_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr)
#define GEM_WARN_ON(expr) (BUILD_BUG_ON_INVALID(expr), 0)
+#define GEM_WARN(condition, format, ...) BUILD_BUG_ON_INVALID(condition)
WARNs can be used as part of an if(), so perhaps
#define GEM_WARN(condition, format, ...) (BUILD_BUG_ON_INVALID(condition), 0)
#define GEM_WARN_ON(expr) GEM_WARN((expr), 0)
Sorry, I just can't resist the "told you so" here.
If you come up with a local pattern that's deceptively similar to a
widely used one, with the crucial difference that you can't use anything
with required side effects in it, you'll screw it up eventually.
if (GEM_WARN_ON(wait_for_engine(engine, 50))) looks completely natural
and "obviously correct" in code, but is dead wrong. This won't be the
last time.
I would also prefer to make it consistent.
There are two other users of GEM_WARN_ON in i915_vma_bind to consider
what to do with, but anyway it would be a much better solution.
My suggestion is to make GEM_WARN_ON and friends that are conditional to
CONFIG_DRM_I915_DEBUG_GEM unusable as expressions. Make them fail to
build within if (...) for both CONFIG_DRM_I915_DEBUG_GEM=y and =n. Then
if you need that kind of construct, handle it with something like:
if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) && condition) {
GEM_WARN(...);
...
}
maybe wrapping that IS_ENABLED bit in a more manageable macro.
Why not simply make it work like a normal WARN_ON? Eg:
#ifdef ...DEBUG_GEM
#define GEM_WARN_ON(expr) WARN_ON(expr)
#else
#define GEM_WARN_ON(expr) (expr)
#endif
Regards,
Tvrtko
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