[Piglit] RFC enhance dmesg handling in piglit

[Daniel Vetter]

On Tue, Nov 12, 2013 at 07:53:58AM -0800, Dylan Baker wrote:
> This series cleans up the dmesg handlingin piglit by implementing a
> module with two classes, one for reading dmesg, and the other that acts
> as a dummy class on non-posix systems, this allows dmesg to just always
> be turned on all the time.
> 
> Secondly this new dmesg class has the ability to filter dmesg entries,
> searching for specific regular expressions and classifying them as
> either 'warns' or 'fails'.
> 
> Currently the filtering is fairly simply, and I expect to have at least
> one more iteration of these patches with more enries for dmesg. It
> curretly as an example marks any test the segfaults as a 'warn', and
> searches for some entries emmitted by the i915 driver and marks them
> 'fail'.

Looks like we're colliding a bit here, cool ;-)

Essentially for i-g-t testcases the rule is that everything in dmesg which
isn't at the debug/info level should make the test fail. Otoh if the tests
succeeds and there's only new info/debug stuff in dmesg, then the result
state shouldn't be set to 'warn'. This is because a lot of our tests are
expected to generate info level messages (e.g. simulated gpu hangs or
module reload). And we often enable full drm debugging when running tests,
which spews a lot.

So either we need to capture the raw dmesg output to be able to pattern
match log-levels (dmesg -r). Or we do the cheap trick I've done in the
patch submitted yesterday of simply filtering out unwanted levels at the
source.

But overall I really want dmesg capture support by default for igt tests.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch