[Intel-gfx] [PATCH v3] drm/i915: Add fault injection support

[Chris Wilson]

On Wed, Mar 16, 2016 at 11:18:04AM +0200, Joonas Lahtinen wrote:
> On ti, 2016-03-15 at 14:14 +0000, Chris Wilson wrote:
> > On Tue, Mar 15, 2016 at 04:01:14PM +0200, Imre Deak wrote:
> > > 
> > > I'm not sure if you want to check all failure paths, I think for that
> > > the existing failslab etc. mechanisms are better suited. This new
> > > option would be used at relatively few well defined places. The option
> > > is a mask since Chris wanted the possibility to mix failures (which
> > > makes sense when injecting a non-fatal failure somewhere). If he
> > > doesn't insist on that possibility I can convert the mask option to a
> > > counter based one identifying a single failure spot instead as you
> > > suggest. Chris?
> > We can extend the counter mechanism by having multiple counters behind
> > i915.inject_load_failure (i.e. =gem:4,driver:10,modeset:1)
> 
> Now that there's a series to split down the init functions nicely, one
> could use the function names directly. By stripping parts of it if
> needed to shorten them.

That's nice. Advantage for using counters is that we can write a test to
iterate over the first thousand and have it run against future
faultpointers. Advantage for using names is that it is readable and
easily extensible.

What we could do for testing is record the available fault injection
points for debugfs and so have the tests automatically adjust (given a
working start point). Overkill?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre