drm/i915: Remove logical HW ID
With the introduction of ctx->engines[] we allow multiple logical contexts to be used on the same engine (e.g. with virtual engines). According to bspec, aach logical context requires a unique tag in order for context-switching to occur correctly between them. [Simple experiments show that it is not so easy to trick the HW into performing a lite-restore with matching logical IDs, though my memory from early Broadwell experiments do suggest that it should be generating lite-restores.] We only need to keep a unique tag for the active lifetime of the context, and for as long as we need to identify that context. The HW uses the tag to determine if it should use a lite-restore (why not the LRCA?) and passes the tag back for various status identifies. The only status we need to track is for OA, so when using perf, we assign the specific context a unique tag. v2: Calculate required number of tags to fill ELSP. Fixes: 976b55f0 ("drm/i915: Allow a context to define its set of engines") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111895 Signed-off-by:Chris Wilson <chris@chris-wilson.co.uk> Acked-by:
Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> Reviewed-by:
Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-14-chris@chris-wilson.co.uk
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