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Since the sandybridge_pcode_read() may be called from skl_pcode_request() inside an atomic context (with preempt disabled), we should avoid hitting any sleeping paths. Currently is being called with a 500ms timeout, irrespective of being inside an atomic context or not. This is reduced down to 500us to play nice with the atomic context, and that appears to be sufficient to keep BAT happy (we have a DRM_ERROR should it timeout), i.e. we do not see any 500us pcode timeouts for normal use. So leave it as a pure spin without having to introduce new code paths to separate atomic/normal contexts. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170411101340.31994-4-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@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.