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Implement proper two stage watermark programming for g4x. As with other pre-SKL platforms, the watermark registers aren't double buffered on g4x. Hence we must sequence the watermark update carefully around plane updates. The code is quite heavily modelled on the VLV/CHV code, with some fairly significant differences due to the different hardware architecture: * g4x doesn't use inverted watermark values * CxSR actually affects the watermarks since it controls memory self refresh in addition to the max FIFO mode * A further HPLL SR mode is possible with higher memory wakeup latency * g4x has FBC2 and so it also has FBC watermarks * max FIFO mode for primary plane only (cursor is allowed, sprite is not) * g4x has no manual FIFO repartitioning * some TLB miss related workarounds are needed for the watermarks Actually the hardware is quite similar to ILK+ in many ways. The most visible differences are in the actual watermakr register layout. ILK revamped that part quite heavily whereas g4x is still using the layout inherited from earlier platforms. Note that we didn't previously enable the HPLL SR on g4x. So in order to not introduce too many functional changes in this patch I've not actually enabled it here either, even though the code is now fully ready for it. We'll enable it separately later on. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170421181432.15216-13-ville.syrjala@linux.intel.com Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.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.