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apple-gmux: Sphinxify docs
Convert asciidoc-formatted docs to rst in accordance with Jonathan's and Jani's effort to use sphinx for kernel-doc rendering in 4.8. Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Acked-by: Darren Hart <dvhart@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/4c1b29986fa77772156b1af0c965d3799e43a47b.1467628307.git.lukas@wunner.de
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@ -31,19 +31,21 @@
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/**
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* DOC: Overview
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*
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* :1: http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
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* :2: http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
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*
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* gmux is a microcontroller built into the MacBook Pro to support dual GPUs:
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* A {1}[Lattice XP2] on pre-retinas, a {2}[Renesas R4F2113] on retinas.
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* A `Lattice XP2`_ on pre-retinas, a `Renesas R4F2113`_ on retinas.
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*
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* (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has
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* dual GPUs but no built-in display.)
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*
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* gmux is connected to the LPC bus of the southbridge. Its I/O ports are
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* accessed differently depending on the microcontroller: Driver functions
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* to access a pre-retina gmux are infixed `_pio_`, those for a retina gmux
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* are infixed `_index_`.
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* to access a pre-retina gmux are infixed ``_pio_``, those for a retina gmux
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* are infixed ``_index_``.
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*
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* .. _Lattice XP2:
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* http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
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* .. _Renesas R4F2113:
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* http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
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*/
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struct apple_gmux_data {
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@ -272,15 +274,15 @@ static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
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/**
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* DOC: Backlight control
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*
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* :3: http://www.ti.com/lit/ds/symlink/lp8543.pdf
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* :4: http://www.ti.com/lit/ds/symlink/lp8545.pdf
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*
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* On single GPU MacBooks, the PWM signal for the backlight is generated by
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* the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended
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* to conserve energy. Hence the PWM signal needs to be generated by a separate
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* backlight driver which is controlled by gmux. The earliest generation
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* MBP5 2008/09 uses a {3}[TI LP8543] backlight driver. All newer models
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* use a {4}[TI LP8545].
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* MBP5 2008/09 uses a `TI LP8543`_ backlight driver. All newer models
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* use a `TI LP8545`_.
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*
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* .. _TI LP8543: http://www.ti.com/lit/ds/symlink/lp8543.pdf
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* .. _TI LP8545: http://www.ti.com/lit/ds/symlink/lp8545.pdf
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*/
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static int gmux_get_brightness(struct backlight_device *bd)
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@ -312,28 +314,20 @@ static const struct backlight_ops gmux_bl_ops = {
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/**
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* DOC: Graphics mux
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*
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* :5: http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
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* :6: http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
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* :7: http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
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* :8: https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
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* :9: http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
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* :10: http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
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* :11: http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
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*
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* On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes
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* either of them to the panel. One of the tricks gmux has up its sleeve is
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* to lengthen the blanking interval of its output during a switch to
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* synchronize it with the GPU switched to. This allows for a flicker-free
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* switch that is imperceptible by the user ({5}[US 8,687,007 B2]).
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* switch that is imperceptible by the user (`US 8,687,007 B2`_).
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*
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* On retinas, muxing is no longer done by gmux itself, but by a separate
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* chip which is controlled by gmux. The chip is triple sourced, it is
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* either an {6}[NXP CBTL06142], {7}[TI HD3SS212] or {8}[Pericom PI3VDP12412].
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* either an `NXP CBTL06142`_, `TI HD3SS212`_ or `Pericom PI3VDP12412`_.
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* The panel is driven with eDP instead of LVDS since the pixel clock
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* required for retina resolution exceeds LVDS' limits.
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*
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* Pre-retinas are able to switch the panel's DDC pins separately.
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* This is handled by a {9}[TI SN74LV4066A] which is controlled by gmux.
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* This is handled by a `TI SN74LV4066A`_ which is controlled by gmux.
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* The inactive GPU can thus probe the panel's EDID without switching over
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* the entire panel. Retinas lack this functionality as the chips used for
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* eDP muxing are incapable of switching the AUX channel separately (see
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@ -344,15 +338,15 @@ static const struct backlight_ops gmux_bl_ops = {
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*
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* The external DP port is only fully switchable on the first two unibody
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* MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an
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* {6}[NXP CBTL06141] which is controlled by gmux. It's the predecessor of the
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* `NXP CBTL06141`_ which is controlled by gmux. It's the predecessor of the
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* eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.
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*
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* The following MacBook Pro generations replaced the external DP port with a
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* combined DP/Thunderbolt port and lost the ability to switch it between GPUs,
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* connecting it either to the discrete GPU or the Thunderbolt controller.
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* Oddly enough, while the full port is no longer switchable, AUX and HPD
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* are still switchable by way of an {10}[NXP CBTL03062] (on pre-retinas
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* MBP8 2011 and MBP9 2012) or two {11}[TI TS3DS10224] (on retinas) under the
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* are still switchable by way of an `NXP CBTL03062`_ (on pre-retinas
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* MBP8 2011 and MBP9 2012) or two `TI TS3DS10224`_ (on retinas) under the
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* control of gmux. Since the integrated GPU is missing the main link,
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* external displays appear to it as phantoms which fail to link-train.
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*
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@ -365,10 +359,19 @@ static const struct backlight_ops gmux_bl_ops = {
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* of this feature.
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*
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* gmux' initial switch state on bootup is user configurable via the EFI
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* variable `gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9` (5th byte,
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* variable ``gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9`` (5th byte,
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* 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to
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* switch the panel and the external DP connector and allocates a framebuffer
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* for the selected GPU.
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*
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* .. _US 8,687,007 B2: http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
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* .. _NXP CBTL06141: http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
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* .. _NXP CBTL06142: http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
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* .. _TI HD3SS212: http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
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* .. _Pericom PI3VDP12412: https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
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* .. _TI SN74LV4066A: http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
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* .. _NXP CBTL03062: http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
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* .. _TI TS3DS10224: http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
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*/
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static void gmux_read_switch_state(struct apple_gmux_data *gmux_data)
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