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authorDaniel Vetter <daniel.vetter@ffwll.ch>2013-05-21 09:52:16 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-05-21 09:52:16 +0200
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parent98304ad186296dc1e655399e28d5973c21db6a73 (diff)
parentc7788792a5e7b0d5d7f96d0766b4cb6112d47d75 (diff)
downloadblackbird-op-linux-e1b73cba13a0cc68dd4f746eced15bd6bb24cda4.tar.gz
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Merge tag 'v3.10-rc2' into drm-intel-next-queued
Backmerge Linux 3.10-rc2 since the various (rather trivial) conflicts grew a bit out of hand. intel_dp.c has the only real functional conflict since the logic changed while dev_priv->edp.bpp was moved around. Also squash in a whitespace fixup from Ben Widawsky for i915_gem_gtt.c, git seems to do something pretty strange in there (which I don't fully understand tbh). Conflicts: drivers/gpu/drm/i915/i915_reg.h drivers/gpu/drm/i915/intel_dp.c Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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+Frequently asked questions about the sunxi clock system
+=======================================================
+
+This document contains useful bits of information that people tend to ask
+about the sunxi clock system, as well as accompanying ASCII art when adequate.
+
+Q: Why is the main 24MHz oscillator gatable? Wouldn't that break the
+ system?
+
+A: The 24MHz oscillator allows gating to save power. Indeed, if gated
+ carelessly the system would stop functioning, but with the right
+ steps, one can gate it and keep the system running. Consider this
+ simplified suspend example:
+
+ While the system is operational, you would see something like
+
+ 24MHz 32kHz
+ |
+ PLL1
+ \
+ \_ CPU Mux
+ |
+ [CPU]
+
+ When you are about to suspend, you switch the CPU Mux to the 32kHz
+ oscillator:
+
+ 24Mhz 32kHz
+ | |
+ PLL1 |
+ /
+ CPU Mux _/
+ |
+ [CPU]
+
+ Finally you can gate the main oscillator
+
+ 32kHz
+ |
+ |
+ /
+ CPU Mux _/
+ |
+ [CPU]
+
+Q: Were can I learn more about the sunxi clocks?
+
+A: The linux-sunxi wiki contains a page documenting the clock registers,
+ you can find it at
+
+ http://linux-sunxi.org/A10/CCM
+
+ The authoritative source for information at this time is the ccmu driver
+ released by Allwinner, you can find it at
+
+ https://github.com/linux-sunxi/linux-sunxi/tree/sunxi-3.0/arch/arm/mach-sun4i/clock/ccmu
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