e8894267cc
Currently we face a severe problem on Braswell that manifests as invalid ppGTT accesses. The code tries to maintain the PDP (page directory pointers) inside the context in two ways, direct write into the context and a pipelined LRI update. The direct write into the context is fundamentally racy as it is unserialised with any access (read or write) the GPU is doing. By asserting that Braswell is not used with vGPU (currently an unsupported platform) we can eliminate the dangerous direct write into the context image and solely use the pipelined update. However, the LRI of the PDP fouls up the GPU, causing it to freeze and take out the machine with "forcewake ack timeouts". This seems possible to workaround by preventing the GPU from sleeping (via means of disabling the power-state management interface, i.e. forcing each ring to remain awake) around the update. Equally, it seems an EMIT_INVALIDATE before the LRI is sufficient to prevent the forcewake errors. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108656 References: https://bugs.freedesktop.org/show_bug.cgi?id=108714 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181207090213.14352-3-chris@chris-wilson.co.uk |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
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.