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a8bd3b884d
Our I915g (early gen3, the oldest machine we have in the farm) is still reporting occasional incoherency performing the following operations: 1) write through GGTT (indirect write into memory) 2) write through either CPU or WC (direct write into memory) 3) read from GGTT (indirect read) Instead of reporting the value from (2), the read from GGTT reports the earlier value written via the GGTT. We have made sure that the writes are flushed from the CPU (commit3a32497f0d("drm/i915/selftests: Provide full mb() around clflush") and commitadd00e6d89("drm/i915: Flush the WCB following a WC write")), but still see the error, just less frequently. The only remaining cache that might be affected here is a chipset cache, so flush that as well. Testcase: igt/drv_selftest/live_coherency #gdg Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180717092655.28417-1-chris@chris-wilson.co.uk
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
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.