[Intel-gfx] [PATCH v4 7/7] drm/i915/guc: change default to using GuC submission if possible

[Chris Wilson]

On Fri, May 13, 2016 at 03:36:35PM +0100, Dave Gordon wrote:
> This patch simply changes the default value of "enable_guc_submission"
> from 0 (never) to -1 (auto). This means that GuC submission will be
> used if the platform has a GuC, the GuC supports the request submission
> protocol, and any required GuC firmwware was successfully loaded. If any
> of these conditions are not met, the driver will fall back to using
> execlist mode.

Why? This is the commit that people will bisect to, it should explain
why guc is preferred. At the moment, with the exception of reduced
context-switch overhead, I don't see any compelling advantage for
enabling guc, just lots of disadvantages.

Enabing a major feature like this, the commit should tell us the
advantages and disadvantages; and future roadmap (but really it should
be compelling in and of itself).
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre