[Beignet] [PATCH] Doc: add OpenCL 2.0 section to readme.

[Song, Ruiling]

Basically looks good, But some typos.

> -----Original Message-----
> From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On Behalf Of
> Yang Rong
> Sent: Friday, January 20, 2017 5:34 PM
> To: beignet at lists.freedesktop.org
> Cc: Yang, Rong R <rong.r.yang at intel.com>
> Subject: [Beignet] [PATCH] Doc: add OpenCL 2.0 section to readme.
> 
> Signed-off-by: Yang Rong <rong.r.yang at intel.com>
> ---
>  docs/Beignet.mdwn | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/docs/Beignet.mdwn b/docs/Beignet.mdwn
> index 64d33dc..b0fea71 100644
> --- a/docs/Beignet.mdwn
> +++ b/docs/Beignet.mdwn
> @@ -158,6 +158,18 @@ Supported Targets
>   * 6th Generation Intel Core Processors "Skylake" and "Kabylake".
>   * 5th Generation Intel Atom Processors "Broxten" or "Apollolake".
> 
> +OpenCL 2.0
> +----------
> +From release v1.3.0, beignet support OpenCL 2.0. By default, OpenCL 2.0
> support is disabled, you can enable it when cmake with option
> +-DENABLE_OPENCL_20=1. Please remember that to enable OpenCL 2.0, there
> are some dependencies. First, OpenCL 2.0 only support the targets
> +from Skylake, include Skylake, Kabylake and Apollolake. Then, only clang
                                                                                                "clang only" is more proper here? I am not sure:)
> support all OpenCL 2.0 feature from 3.9. So to enable OpenCL 2.0,
> +you must update LLVM/clang to 3.9 or later. And also requeired libdrm at least
                                                                                                       "requires"
> 2.4.66.
> +After enable OpenCL 2.0, beignet complies with OpenCL 2.0 spec, but some
> OpenCL 2.0 features is simulated by software, there is no performance
                                         "are"
> +gain, such as pipe and device queues, especially device queues.
> +If you build beignet with enable OpenCL 2.0 and your kernel don't use the
		           "with OpenCL 2.0 enabled"
> OpenCL 2.0 features, please pass a build option -cl-std=CL1.2 for
> +performance, the OpenCL 2.0 uses more registers and has lots of long
                                                  "has lots of int64 operations" may be more clear
> operations, which may hurt performance, and beignet will continue to improve
> +OpenCL 2.0 performance.
> +
>  Known Issues
>  ------------
> 
> --
> 2.1.4
> 
> _______________________________________________
> Beignet mailing list
> Beignet at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/beignet