[Intel-gfx] [PATCH 4/8] drm/i915: Rename ctx->id to ctx->handle

[Chris Wilson]

On Thu, Jun 26, 2014 at 02:24:15PM +0100, oscar.mateo at intel.com wrote:
> From: Oscar Mateo <oscar.mateo at intel.com>
> 
> This is an Execlists preparatory patch, since they make context ID become an
> overloaded term:
> 
> - In the software, it was used to distinguish which context userspace was
>   trying to use.
> - In the BSpec, the term is used to describe the 20-bits long field the
>   hardware uses to it to discriminate the contexts that are submitted to
>   the ELSP and inform the driver about their current status (via Context
>   Switch Interrupts and Context Status Buffers).
> 
> Initially, I tried to make the different meanings converge, but it proved
> impossible:
> 
> - The software ctx->id is per-filp, while the hardware one needs to be
>   globally unique.
> - Also, we multiplex several backing states objects per intel_context,
>   and all of them need unique HW IDs.
> - I tried adding a per-filp ID and then composing the HW context ID as:
>   ctx->id + file_priv->id + ring->id, but the fact that the hardware only
>   uses 20-bits means we have to artificially limit the number of filps or
>   contexts the userspace can create.
> 
> The ctx->handle bits are done with this Cocci patch (plus manual frobbing
> of the struct declaration):
> 
> 	@@
> 	struct intel_context c;
> 	@@
> 	- (c).id
> 	+ c.handle
> 
> 	@@
> 	struct intel_context *c;
> 	@@
> 	- (c)->id
> 	+ c->handle
> 
> Also, while we are at it, s/DEFAULT_CONTEXT_ID/DEFAULT_CONTEXT_HANDLE.
> 
> Signed-off-by: Oscar Mateo <oscar.mateo at intel.com>

Let's go whole hog here and call it ctx->user_handle.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre