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One of the differences I spotted for GEN8+ platforms when compared to older platforms is that spec for BDW+ includes this sentence: "The first CRC done indication after CRC is first enabled is from only a partial frame, so it will not have the expected CRC result." This is an indication that on BDW+ platforms, by the time we receive the interrupt the CRC is not accurate yet for the full frame. That would be ok, because we are already skipping the first CRC for all platforms. However the comment on the code state that it is for some unknown reason. Also, on CHV (gen8 lp) we were already discarding the second CRC as well to make sure we have a reliable CRC on hand. So based on all ou tests and bugs it seems that it is not on CHV that needs to discard 2 first CRCs, but all BDW+ platforms. Starting on SKL we have this CRC done bit (24), but the experiments around the use of this bit wasn't that stable as just discarding the second CRC. So, let's for now just move with CHV solution for all gen8+ platforms and make our CI a bit more stable. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102374 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101309 Cc: Mika Kahola <mika.kahola@intel.com> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Tested-by: Mika Kahola <mika.kahola@intel.com> Reviewed-by: Mika Kahola <mika.kahola@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20170928002040.7917-1-rodrigo.vivi@intel.com
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.