[Intel-gfx] [PATCHv9] drm/i915: Added Programming of the MOCS

[Damien Lespiau]

On Fri, Jul 10, 2015 at 08:13:11PM +0300, Francisco Jerez wrote:
> From: Peter Antoine <peter.antoine at intel.com>
> 
> This change adds the programming of the MOCS registers to the gen 9+
> platforms. The set of MOCS configuration entries introduced by this
> patch is intended to be minimal but sufficient to cover the needs of
> current userspace - i.e. a good set of defaults. It is expected to be
> extended in the future to provide further default values or to allow
> userspace to redefine its private MOCS tables based on its demand for
> additional caching configurations. In this setup, userspace should
> only utilize the first N entries, higher entries are reserved for
> future use.
> 
> It creates a fixed register set that is programmed across the different
> engines so that all engines have the same table. This is done as the
> main RCS context only holds the registers for itself and the shared
> L3 values. By trying to keep the registers consistent across the
> different engines it should make the programming for the registers
> consistent.
> 
> v2:
> -'static const' for private data structures and style changes.(Matt Turner)
> v3:
> - Make the tables "slightly" more readable. (Damien Lespiau)
> - Updated tables fix performance regression.
> v4:
> - Code formatting. (Chris Wilson)
> - re-privatised mocs code. (Daniel Vetter)
> v5:
> - Changed the name of a function. (Chris Wilson)
> v6:
> - re-based
> - Added Mesa table entry (skylake & broxton) (Francisco Jerez)
> - Tidied up the readability defines (Francisco Jerez)
> - NUMBER of entries defines wrong. (Jim Bish)
> - Added comments to clear up the meaning of the tables (Jim Bish)
> 
> Signed-off-by: Peter Antoine <peter.antoine at intel.com>
> 
> v7 (Francisco Jerez):
> - Don't write L3-specific MOCS_ESC/SCC values into the e/LLC control
>   tables.  Prefix L3-specific defines consistently with L3_ and
>   e/LLC-specific defines with LE_ to avoid this kind of confusion in
>   the future.
> - Change L3CC WT define back to RESERVED (matches my hardware
>   documentation and the original patch, probably a misunderstanding
>   of my own previous comment).
> - Drop Android tables, define new minimal tables more suitable for the
>   open source stack.
> - Add comment that the MOCS tables are part of the kernel ABI.
> - Move intel_logical_ring_begin() and _advance() calls one level down
>   (Chris Wilson).
> - Minor formatting and style fixes.
> v8 (Francisco Jerez):
> - Add table size sanity check to emit_mocs_control/l3cc_table() (Chris
>   Wilson).
> - Add comment about undefined entries being implicitly set to uncached
>   for forwards compatibility.
> v9 (Francisco Jerez):
> - Minor style fixes.

What's happening here? are we ready to commit to this ABI?

-- 
Damien