[Intel-gfx] [PATCH v4] drm/i915/mocs: Program MOCS for all engines on init

[Chris Wilson]

On Mon, Mar 14, 2016 at 03:11:02PM +0000, Peter Antoine wrote:
> Allow for the MOCS to be programmed for all engines.
> Currently we program the MOCS when the first render batch
> goes through. This works on most platforms but fails on
> platforms that do not run a render batch early,
> i.e. headless servers. The patch now programs all initialised engines
> on init and the RCS is programmed again within the initial batch. This
> is done for predictable consistency with regards to the hardware
> context.
> 
> Hardware context loading sets the values of the MOCS for RCS
> and L3CC. Programming them from within the batch makes sure that
> the render context is valid, no matter what the previous state of
> the saved-context was.
> 
> v2: posted correct version to the mailing list.
> v3: moved programming to within engine->init_hw() (Chris Wilson)
> v4: code formatting and white-space changes. (Chris Wilson)
> 
> Signed-off-by: Peter Antoine <peter.antoine at intel.com>

So testcase?

Execute a bunch of MI_STORE_REGISTER_MEM on the various rings in a fresh
context each time and confirm the ABI for the first N locations.

Repeat across suspend/resume (i.e. make sure the context image maintain
the register state). Then verify that freshly constructed contexts also
have the correct settings after resume.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre