Update README for the command parser in drm kernel.

Signed-off-by: Yang Rong <rong.r.yang@intel.com>
Reviewed-by: Zhigang Gong <zhigang.gong@linux.intel.com>

diff --git a/docs/Beignet.mdwn b/docs/Beignet.mdwn
index 1cbffa4..d47f3dc 100644 (file)
--- a/docs/Beignet.mdwn
+++ b/docs/Beignet.mdwn
@@ -72,6 +72,14 @@ really recent C++11 features, you may expect problems with older compilers. Last
 time I tried, the code breaks ICC 12 and Clang with internal compiler errors
 while compiling anonymous nested lambda functions.
 
+**Note about Linux Kernel**
+* There is a known issue in some versions of linux kernel which enable register whitelist feature
+  but miss some necessary registers which are required for beignet. The problematic version are
+  around 3.15 and 3.16 which have commit f0a346b... but haven't commit c9224f... If it is the case,
+  you can apply c9224f... manually and rebuild the kernel or just disable the parse command by
+  invoke the following command (use Ubuntu as an example):
+  `# echo 0 > /sys/module/i915/parameters/enable_cmd_parser`
+
 
 How to build and install
 ------------------------