[Intel-gfx] [PATCH v2 1/7] drm/i915/gen8: Add infrastructure to initialize WA batch buffers

[Chris Wilson]

On Fri, May 29, 2015 at 07:03:19PM +0100, Arun Siluvery wrote:
> This patch adds functions to setup WA batch buffers but they are not yet
> enabled in this patch. Some of the WA are to be applied during context save
> but before restore and some at the end of context save/restore but before
> executing the instructions in the ring, WA batch buffers are created for
> this purpose and these WA cannot be applied using normal means.
> 
> Signed-off-by: Namrta <namrta.salonie at intel.com>
> Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h  |   3 ++
>  drivers/gpu/drm/i915/intel_lrc.c | 101 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 104 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 731b5ce..dd4b31d 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -814,6 +814,9 @@ struct intel_context {
>  
>  	/* Execlists */
>  	bool rcs_initialized;
> +	struct intel_ringbuffer *indirect_ctx_wa_bb;
> +	struct intel_ringbuffer *per_ctx_wa_bb;

Eh? They are only command sequences whose starting addresses you encode
into the execlists context. Why have you allocated a ringbuf not an
object? Why have you allocated 2 pages when you only need one, and could
even find space elsewhere in the context....

And these should be pinned alongside the context *not permanently*.

I want a debug mode that limits us to say 16M of GGTT space so that
these address space leaks are easier to demonstrate in practice.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre