[Intel-gfx] [PATCH 17/49] drm/i915/bdw: A bit more advanced context init/fini

[Mateo Lozano, Oscar]

> > --- a/drivers/gpu/drm/i915/i915_lrc.c
> > +++ b/drivers/gpu/drm/i915/i915_lrc.c
> > @@ -41,7 +41,45 @@
> >  #include <drm/i915_drm.h>
> >  #include "i915_drv.h"
> >
> > +#define GEN8_LR_CONTEXT_SIZE (21 * PAGE_SIZE)
> 
> I'm a bit puzzled by that number:
>   - I found a sentence saying: "the Context Image for the rendering
>     engine consists of 20 4K pages", which seems that it includes the
>     HWS page (on the same page it says context layout = HWS Page +
>     register state context).
>   - When looking at the register state context for the render engine:
>     18096 dwords -> 18 pages, so in total it'd be 19 pages (need to add
>     the HWS Page)
>   - Clearly I must be missing something :)
>   - That's only for the render engine, other engines have a much smaller
>     context, smaller enough that it's worth looking at their exact size.
>   - It'd be nice to work out the real size from the *CXT_*SIZE
>     registers.

Hmmmm... I´ll try to get the real context sizes from the registers and compare. At least for RCS, VCS and BCS since there doesn´t seem to be a register for VECS?

-- Oscar