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

Mateo Lozano, Oscar
2014-04-01T13:49:03Z

> > --- 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