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This change implements support for per-engine reset as an initial, less intrusive hang recovery option to be attempted before falling back to the legacy full GPU reset recovery mode if necessary. This is only supported from Gen8 onwards. Hangchecker determines which engines are hung and invokes error handler to recover from it. Error handler schedules recovery for each of those engines that are hung. The recovery procedure is as follows, - identifies the request that caused the hang and it is dropped - force engine to idle: this is done by issuing a reset request - reset the engine - re-init the engine to resume submissions. If engine reset fails then we fall back to heavy weight full gpu reset which resets all engines and reinitiazes complete state of HW and SW. v2: Rebase. v3: s/*engine_reset*/*reset_engine*/; freeze engine and irqs before calling i915_gem_reset_engine (Chris). v4: Rebase, modify i915_gem_reset_prepare to use a ring mask and reuse the function for reset_engine. v5: intel_reset_engine_start/cancel instead of request/unrequest_reset. v6: Clean up reset_engine function to not require mutex, i.e. no need to call revoke/restore_fences and _retire_requests (Chris). v7: Remove leftovers from v5, i.e. no need to disable irq, hold forcewake or wakeup the handoff bit (Chris). v8: engine_retire_requests should be (and it was) static; explain that we have to re-init the engine after reset, which is why the init_hw call is needed; check reset-in-progress flag (Chris). v9: Rebase, include code to pass the active request to gem_reset_engine (as it is already done in full reset). Remove unnecessary intel_reset_engine_start/cancel, these are executed as part of the reset. v10: Rebase, use the right I915_RESET_ENGINE flag. v11: Fixup to call reset_finish_engine even on error. Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Signed-off-by: Tomas Elf <tomas.elf@intel.com> Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com> Signed-off-by: Michel Thierry <michel.thierry@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170615201828.23144-6-michel.thierry@intel.com Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: http://patchwork.freedesktop.org/patch/msgid/20170620095751.13127-6-chris@chris-wilson.co.uk
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.