[Intel-gfx] [PATCH] drm/i915: Add two-stage ILK-style watermark programming (v10)

[Maarten Lankhorst]

Op 06-01-16 om 20:34 schreef Matt Roper:
> In addition to calculating final watermarks, let's also pre-calculate a
> set of intermediate watermark values at atomic check time.  These
> intermediate watermarks are a combination of the watermarks for the old
> state and the new state; they should satisfy the requirements of both
> states which means they can be programmed immediately when we commit the
> atomic state (without waiting for a vblank).  Once the vblank does
> happen, we can then re-program watermarks to the more optimal final
> value.
>
> v2: Significant rebasing/rewriting.
>
> v3:
>  - Move 'need_postvbl_update' flag to CRTC state (Daniel)
>  - Don't forget to check intermediate watermark values for validity
>    (Maarten)
>  - Don't due async watermark optimization; just do it at the end of the
>    atomic transaction, after waiting for vblanks.  We do want it to be
>    async eventually, but adding that now will cause more trouble for
>    Maarten's in-progress work.  (Maarten)
>  - Don't allocate space in crtc_state for intermediate watermarks on
>    platforms that don't need it (gen9+).
>  - Move WaCxSRDisabledForSpriteScaling:ivb into intel_begin_crtc_commit
>    now that ilk_update_wm is gone.
>
> v4:
>  - Add a wm_mutex to cover updates to intel_crtc->active and the
>    need_postvbl_update flag.  Since we don't have async yet it isn't
>    terribly important yet, but might as well add it now.
>  - Change interface to program watermarks.  Platforms will now expose
>    .initial_watermarks() and .optimize_watermarks() functions to do
>    watermark programming.  These should lock wm_mutex, copy the
>    appropriate state values into intel_crtc->active, and then call
>    the internal program watermarks function.
>
> v5:
>  - Skip intermediate watermark calculation/check during initial hardware
>    readout since we don't trust the existing HW values (and don't have
>    valid values of our own yet).
>  - Don't try to call .optimize_watermarks() on platforms that don't have
>    atomic watermarks yet.  (Maarten)
>
> v6:
>  - Rebase
>
> v7:
>  - Further rebase
>
> v8:
>  - A few minor indentation and line length fixes
>
> v9:
>  - Yet another rebase since Maarten's patches reworked a bunch of the
>    code (wm_pre, wm_post, etc.) that this was previously based on.
>
> v10:
>  - Move wm_mutex to dev_priv to protect against racing commits against
>    disjoint CRTC sets. (Maarten)
>  - Drop unnecessary clearing of cstate->wm.need_postvbl_update (Maarten)
>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
>
Pushed, thanks.