[Intel-gfx] [PATCH 2/3] drm/i915/guc: Handle interrupt based logging with lack of SSE4.1, relay and other setup

[Chris Wilson]

Quoting Sagar Arun Kamble (2018-01-31 06:14:38)
> On some systems like skl-gvtdvm, SSE4.1 movntdqa might not be available.
> movntdqa is needed for efficient capture of the logs from uncached GuC
> log buffer. GuC init was tied with this support and other setup needed
> for interrupt based GuC log capture like relay channel/file support and
> uncached mapping support. With this patch, GuC init is now unblocked from
> lack of this support.
> SSE and relay support init/fini is now being done by new functions
> intel_guc_log_init|fini_runtime() which makes relay functions static.
> We have introduced two states "supported" and "enabled". Supported is set
> when we have SSE4.1 support and have relay, GuC log, WC mapping available.
> Enabled is set when support is present and user has requested logging
> through i915_modparams.guc_log_level.
> While at this change, fixed unwind order in intel_uc_fini_misc.

Downside would appear to be the loss of feedback in i915.guc_log_level
when it fail? Otherwise, looks tidy enough.
-Chris