--------------------------------------------------------------------- Intel Corporation (UK) Limited Registered No. 1134945 (England) Registered Office: Pipers Way, Swindon SN3 1RJ VAT No: 860 2173 47 > -----Original Message----- > From: Daniel Vetter [mailto:daniel.vetter@xxxxxxxx] On Behalf Of Daniel > Vetter > Sent: Tuesday, June 17, 2014 10:40 AM > To: Mateo Lozano, Oscar > Cc: Daniel Vetter; Chris Wilson; intel-gfx@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH 51/53] drm/i915/bdw: Document Logical > Rings, LR contexts and Execlists > > On Tue, Jun 17, 2014 at 08:22:55AM +0000, Mateo Lozano, Oscar wrote: > > > > > -----Original Message----- > > > From: Daniel Vetter [mailto:daniel.vetter@xxxxxxxx] On Behalf Of > > > Daniel Vetter > > > Sent: Monday, June 16, 2014 6:56 PM > > > To: Mateo Lozano, Oscar > > > Cc: Chris Wilson; intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > > Subject: Re: [PATCH 51/53] drm/i915/bdw: Document > > > Logical Rings, LR contexts and Execlists > > > > > > On Mon, Jun 16, 2014 at 03:24:26PM +0000, Mateo Lozano, Oscar > wrote: > > > > > -----Original Message----- > > > > > From: Chris Wilson [mailto:chris@xxxxxxxxxxxxxxxxxx] > > > > > Sent: Friday, June 13, 2014 5:51 PM > > > > > To: Mateo Lozano, Oscar > > > > > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > > > > Subject: Re: [PATCH 51/53] drm/i915/bdw: Document > > > > > Logical Rings, LR contexts and Execlists > > > > > > > > > > On Fri, Jun 13, 2014 at 04:38:09PM +0100, oscar.mateo@xxxxxxxxx > > > wrote: > > > > > > +/** > > > > > > + * intel_execlists_ctx_id() - get the Execlists Context ID > > > > > > + * @ctx_obj: Logical Ring Context backing object. > > > > > > + * > > > > > > + * Do not confuse with ctx->id! Unfortunately we have a name > > > > > > +overload > > > > > > + * here: the old context ID we pass to userspace as a handler > > > > > > +so that > > > > > > + * they can refer to a context, and the new context ID we > > > > > > +pass to the > > > > > > + * ELSP so that the GPU can inform us of the context status > > > > > > +via > > > > > > + * interrupts. > > > > > > + * > > > > > > + * Return: 20-bits globally unique context ID. > > > > > > + */ > > > > > > > > > > Use tag for the ctx id we pass around in hw? > > > > > -Chris > > > > > > > > I also tried other names, like "submission id", but it confuses > > > > people when they search for in the BSpec. Maybe changing ctx->id > > > > to ctx->tag, and leaving id for the hardware? > > > > > > I think Chris' idea was to reuse the id from the idr for the hw tag. > > > But I guess that fails because our idr is global. > > > > > > Or I'm totally confused. > > > > > > I'd vote for hw_ctx_id or something. > > > -Daniel > > > > In the first version of the series I tried to reuse the id from the > > idr, but that was a bad idea because the id we pass to the hw has to > > be globally unique, while our idr is per file_priv. What I did is > > adding an id field to the file_priv and then generating the hw ctx id > > by using some bits from ctx->id, some from file_priv->id and finally > > some from > > ring->id (since we multiplex several hw contexts inside our struct > > intel_context). But the ELSP context descriptor only allows 20 bits > > for the id, so I had to limit the maximum number of contexts, files or > > rings artificially (ugly). > > Considerations like this should be somewhere in the commit message. > Especially when it's all stuff you've discovered before review started and > hence doesn't have a public record anywhere. Nope, I discovered this *after* review started: v1 used the Frankenstein-style context id, v2 didn´t. The comment appears in the commit message for " drm/i915/bdw: Implement context switching (somewhat) ": v3: Use LRCA[31:12] as hwCtxId[19:0]. This guarantees that the HW context ID we submit to the ELSP is globally unique and != 0 (Bspec requirements of the software use-only bits of the Context ID in the Context Descriptor Format) without the hassle of the previous submission Id construction. > > Another proposal: s/ctx->id/ctx->handle. After all, our ctx->id software > construct is just a userspace handle... > > Not sure either is clearer really. As long as there's a clear disdinction > between the hw id and the userspace handle I'm ok, maybe augmented with > some comments to explain the struct fields in the header. > -Daniel I´ll go with s/ctx->id/ctx->handle and the comments then (IMHO, it´s clear enough). _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
