Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux

Pull drm updates from Dave Airlie:
 "This is the main drm pull request for 4.5.  I don't think I've missed
  anything too major, I'm mostly back at work now but I'll probably get
  some sleep in 5 years time.

  Summary:

  New drivers:
   - etnaviv:

     GPU driver for the 3D core on the Vivante core used in numerous
     ARM boards.

  Highlights:

  Core:
   - Atomic suspend/resume helpers
   - Move the headers to using userspace friendlier types.
   - Documentation updates
   - Lots of struct_mutex removal.
   - Bunch of DP MST fixes from AMD.

  Panel:
   - More DSI helpers
   - Support for some new basic panels

  i915:
   - Basic Kabylake support
   - DP link training and detect code refactoring
   - fbc/psr fixes
   - FIFO underrun fixes
   - SDE interrupt handling fixes
   - dma-buf/fence support in pageflip path.
   - GPU side for MST audio support

  radeon/amdgpu:
   - Drop UMS support
   - GPUVM/Scheduler optimisations
   - Initial Powerplay support for Tonga/Fiji/CZ/ST
   - ACP audio prerequisites

  nouveau:
   - GK20a instmem improvements
   - PCIE link speed change support

  msm:
   - DSI support for msm8960/apq8064

  tegra:
   - Host1X support for Tegra210 SoC

  vc4:
   - 3D acceleration support

  armada:
   - Get rid of struct mutex

  tda998x:
   - Atomic modesetting support
   - TMDS clock limitations

  omapdrm:
   - Atomic modesetting support
   - improved TILER performance

  rockchip:
   - RK3036 VOP support
   - Atomic modesetting support
   - Synopsys DW MIPI DSI support

  exynos:
   - Runtime PM support
   - of_graph binding for DP panels
   - Cleanup of IPP code
   - Configurable plane support
   - Kernel panic fixes at release time"

* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (711 commits)
  drm/fb_cma_helper: Remove implicit call to disable_unused_functions
  drm/amdgpu: add missing irq.h include
  drm/vmwgfx: Fix a width / pitch mismatch on framebuffer updates
  drm/vmwgfx: Fix an incorrect lock check
  drm: nouveau: fix nouveau_debugfs_init prototype
  drm/nouveau/pci: fix check in nvkm_pcie_set_link
  drm/amdgpu: validate duplicates first
  drm/amdgpu: move VM page tables to the LRU end on CS v2
  drm/ttm: add ttm_bo_move_to_lru_tail function v2
  drm/ttm: fix adding foreign BOs to the swap LRU
  drm/ttm: fix adding foreign BOs to the LRU during init v2
  drm/radeon: use kobj_to_dev()
  drm/amdgpu: use kobj_to_dev()
  drm/amdgpu/cz: force vce clocks when sclks are forced
  drm/amdgpu/cz: force uvd clocks when sclks are forced
  drm/amdgpu/cz: add code to enable forcing VCE clocks
  drm/amdgpu/cz: add code to enable forcing UVD clocks
  drm/amdgpu: fix lost sync_to if scheduler is enabled.
  drm/amd/powerplay: fix static checker warning for return meaningless value.
  drm/sysfs: use kobj_to_dev()
  ...

drivers/platform/x86/apple-gmux.c

@@ -3,6 +3,7 @@
  *
  *  Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
  *  Copyright (C) 2010-2012 Andreas Heider <andreas@meetr.de>
+ *  Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2 as
@@ -26,6 +27,24 @@
 #include <acpi/video.h>
 #include <asm/io.h>
 
+/**
+ * DOC: Overview
+ *
+ * :1:  http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
+ * :2:  http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
+ *
+ * gmux is a microcontroller built into the MacBook Pro to support dual GPUs:
+ * A {1}[Lattice XP2] on pre-retinas, a {2}[Renesas R4F2113] on retinas.
+ *
+ * (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has
+ * dual GPUs but no built-in display.)
+ *
+ * gmux is connected to the LPC bus of the southbridge. Its I/O ports are
+ * accessed differently depending on the microcontroller: Driver functions
+ * to access a pre-retina gmux are infixed `_pio_`, those for a retina gmux
+ * are infixed `_index_`.
+ */
+
 struct apple_gmux_data {
 	unsigned long iostart;
 	unsigned long iolen;
@@ -247,6 +266,20 @@ static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
 	return false;
 }
 
+/**
+ * DOC: Backlight control
+ *
+ * :3:  http://www.ti.com/lit/ds/symlink/lp8543.pdf
+ * :4:  http://www.ti.com/lit/ds/symlink/lp8545.pdf
+ *
+ * On single GPU MacBooks, the PWM signal for the backlight is generated by
+ * the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended
+ * to conserve energy. Hence the PWM signal needs to be generated by a separate
+ * backlight driver which is controlled by gmux. The earliest generation
+ * MBP5 2008/09 uses a {3}[TI LP8543] backlight driver. All newer models
+ * use a {4}[TI LP8545].
+ */
+
 static int gmux_get_brightness(struct backlight_device *bd)
 {
 	struct apple_gmux_data *gmux_data = bl_get_data(bd);
@@ -273,6 +306,68 @@ static const struct backlight_ops gmux_bl_ops = {
 	.update_status = gmux_update_status,
 };
 
+/**
+ * DOC: Graphics mux
+ *
+ * :5:  http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
+ * :6:  http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
+ * :7:  http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
+ * :8:  https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
+ * :9:  http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
+ * :10: http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
+ * :11: http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
+ *
+ * On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes
+ * either of them to the panel. One of the tricks gmux has up its sleeve is
+ * to lengthen the blanking interval of its output during a switch to
+ * synchronize it with the GPU switched to. This allows for a flicker-free
+ * switch that is imperceptible by the user ({5}[US 8,687,007 B2]).
+ *
+ * On retinas, muxing is no longer done by gmux itself, but by a separate
+ * chip which is controlled by gmux. The chip is triple sourced, it is
+ * either an {6}[NXP CBTL06142], {7}[TI HD3SS212] or {8}[Pericom PI3VDP12412].
+ * The panel is driven with eDP instead of LVDS since the pixel clock
+ * required for retina resolution exceeds LVDS' limits.
+ *
+ * Pre-retinas are able to switch the panel's DDC pins separately.
+ * This is handled by a {9}[TI SN74LV4066A] which is controlled by gmux.
+ * The inactive GPU can thus probe the panel's EDID without switching over
+ * the entire panel. Retinas lack this functionality as the chips used for
+ * eDP muxing are incapable of switching the AUX channel separately (see
+ * the linked data sheets, Pericom would be capable but this is unused).
+ * However the retina panel has the NO_AUX_HANDSHAKE_LINK_TRAINING bit set
+ * in its DPCD, allowing the inactive GPU to skip the AUX handshake and
+ * set up the output with link parameters pre-calibrated by the active GPU.
+ *
+ * The external DP port is only fully switchable on the first two unibody
+ * MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an
+ * {6}[NXP CBTL06141] which is controlled by gmux. It's the predecessor of the
+ * eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.
+ *
+ * The following MacBook Pro generations replaced the external DP port with a
+ * combined DP/Thunderbolt port and lost the ability to switch it between GPUs,
+ * connecting it either to the discrete GPU or the Thunderbolt controller.
+ * Oddly enough, while the full port is no longer switchable, AUX and HPD
+ * are still switchable by way of an {10}[NXP CBTL03062] (on pre-retinas
+ * MBP8 2011 and MBP9 2012) or two {11}[TI TS3DS10224] (on retinas) under the
+ * control of gmux. Since the integrated GPU is missing the main link,
+ * external displays appear to it as phantoms which fail to link-train.
+ *
+ * gmux receives the HPD signal of all display connectors and sends an
+ * interrupt on hotplug. On generations which cannot switch external ports,
+ * the discrete GPU can then be woken to drive the newly connected display.
+ * The ability to switch AUX on these generations could be used to improve
+ * reliability of hotplug detection by having the integrated GPU poll the
+ * ports while the discrete GPU is asleep, but currently we do not make use
+ * of this feature.
+ *
+ * gmux' initial switch state on bootup is user configurable via the EFI
+ * variable `gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9` (5th byte,
+ * 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to
+ * switch the panel and the external DP connector and allocates a framebuffer
+ * for the selected GPU.
+ */
+
 static int gmux_switchto(enum vga_switcheroo_client_id id)
 {
 	if (id == VGA_SWITCHEROO_IGD) {
@@ -288,6 +383,14 @@ static int gmux_switchto(enum vga_switcheroo_client_id id)
 	return 0;
 }
 
+/**
+ * DOC: Power control
+ *
+ * gmux is able to cut power to the discrete GPU. It automatically takes care
+ * of the correct sequence to tear down and bring up the power rails for
+ * core voltage, VRAM and PCIe.
+ */
+
 static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
 				   enum vga_switcheroo_state state)
 {
@@ -352,6 +455,16 @@ static const struct vga_switcheroo_handler gmux_handler = {
 	.get_client_id = gmux_get_client_id,
 };
 
+/**
+ * DOC: Interrupt
+ *
+ * gmux is also connected to a GPIO pin of the southbridge and thereby is able
+ * to trigger an ACPI GPE. On the MBP5 2008/09 it's GPIO pin 22 of the Nvidia
+ * MCP79, on all following generations it's GPIO pin 6 of the Intel PCH.
+ * The GPE merely signals that an interrupt occurred, the actual type of event
+ * is identified by reading a gmux register.
+ */
+
 static inline void gmux_disable_interrupts(struct apple_gmux_data *gmux_data)
 {
 	gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,