f9228f7658
On gen7, including Haswell, the MI_FLUSH_DW command is not synchronous with the command streamer nor is there an option to make it so. To hide this we add a large delay on the CS so that the breadcrumb should always be visible before the interrupt. However, that does not seem to be enough to ensure the memory is actually coherent with the read of the breadcrumb. The breadcrumb update is a post-sync op... Throw in a preliminary MI_FLUSH_DW before the breadcrumb update in the hope that helps. References: https://bugs.freedesktop.org/show_bug.cgi?id=112147 Testcase: igt/i915_selftest/live_blt Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191111120957.17732-1-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.
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.