[Intel-gfx] [PATCH v2] drm/i915/mocs: Program MOCS for all engines on init

[Chris Wilson]

On Thu, Mar 10, 2016 at 08:22:58PM +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.
> 
> Signed-off-by: Peter Antoine <peter.antoine at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c   |   3 +
>  drivers/gpu/drm/i915/intel_mocs.c | 138 ++++++++++++++++++++++++++++++++++----
>  drivers/gpu/drm/i915/intel_mocs.h |   1 +
>  3 files changed, 130 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index b854af2..05c9fcb 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -32,6 +32,7 @@
>  #include "i915_vgpu.h"
>  #include "i915_trace.h"
>  #include "intel_drv.h"
> +#include "intel_mocs.h"
>  #include <linux/shmem_fs.h>
>  #include <linux/slab.h>
>  #include <linux/swap.h>
> @@ -4882,6 +4883,8 @@ i915_gem_init_hw(struct drm_device *dev)
>  			goto out;
>  	}
>  
> +	intel_program_mocs_engines(dev);

Registers to be written when enabling the engine are called from
engine->init_hw() in the line above. Please add this state there, which
can then be specialised via vfunc if so desired.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre