[PATCH] drm: Do not use BUG_ON(!spin_is_locked())

Dave Airlie airlied at gmail.com
Sun Aug 31 23:18:35 PDT 2014

>ssert_spin_locked() is a better option.
>> > >
>> >
>> > Unless there's a bug, assert_spin_locked() is just going to incur an
>> > unnecessary cost every time it is called at runtime.  My suggestion was
>> > to
>> > limit that check only to debugging kernels that include enabling lockdep
>> > when tracking down problems rather than needlessly evaluating the
>> > conditional every time when there are no bugs.
>> My experience with gpu drivers (i915) has been that hw and the software
>> running it is varied enough that almost always it's better to
>> unconditionally enable this stuff. I much prefer assert_spin_locked and
>> friends over the lockdep versions since enabling full lockdep is not
>> something you usually do. Especially not normal users, and we rely upon
>> them for testing the old stuff. Furthermore for the modeset code the
>> overhead is totally irrelevant since we're doing metric piles of register
>> reads and writes in there anyway.

Did anything translate into an R-b here?


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