Document what I've learned so far about the gmux so that we can
collaboratively reverse-engineer its remaining unknown bits
without everyone having to start from scratch.
The DOC sections are bound together in the gpu.tmpl DocBook
under a new vga_switcheroo "Handlers" chapter. Eventually
this should be amended with documentation about the four other
handlers that exist so far (nouveau v1 DSM, nouveau Optimus DSM,
radeon ATPX, amdgpu ATPX).
Requires kernel-doc with asciidoc support.
The EFI variable was reverse-engineered by Bruno Bierbaumer
<bruno@bierbaumer.net> and Andreas Heider <andreas@meetr.de>.
Some of the remaining open questions:
* How are vblank intervals synchronized on retinas to achieve seamless
switching? Is the DP mux capable of this? It's not mentioned in the
data sheets. Or is it done at the OS level, i.e. do we have to
synchronize vblank intervals between DRM drivers? There's a signal
coming from the panel connector and going into gmux, could this be
the vblank signal as received by the panel to properly time the
switch?
* On retinas there's an I2C bus between gmux and the connector of the
right I/O board, apparently leading to the Parade PS8401A HDMI
repeater. What is this for, is it controlled via gmux registers?
Data sheet:
http://www.paradetech.com/products/jitter-cleaning-repeaters/ps8401/
* On retinas there's an I2C bus between gmux and the LED driver.
Pre-retinas connected the LED driver to SMBUS. Are there additional
gmux registers on retinas to control it?
* The MacPro6,1 2013 also has a gmux, the same Renesas R4F2113 as the
retina MacBook Pro. The Mac Pro doesn't have a built-in display,
so what is its purpose? Power control of the dual FirePro GPUs?
Switching of the external DP/Thunderbolt ports? The iFixit teardown
clearly shows one TI HD3SS212 DisplayPort mux on the logic board next
to one of the three Thunderbolt controllers. However six muxes would
be necessary to switch all six ports between GPUs. The mux is probably
necessary for one of the display configurations allowed by Apple,
but which one?
https://www.ifixit.com/Teardown/Mac+Pro+Late+2013+Teardown/20778https://d3nevzfk7ii3be.cloudfront.net/igi/fELBTnt31QhnDsqq.hugehttps://support.apple.com/en-us/HT202801
* Registers we haven't decoded yet:
0x700 32 Bit configmap?
0x708 32 Bit power sequence?
0x712 8 Bit status of clock from panel on retinas?
0x713 8 Bit dito?
0x724 16 Bit backlight, raw value?
0x760 32 Bit backlight
0x764 32 Bit backlight
0x768 8 Bit backlight
0x76a 16 Bit backlight
0x76c 16 Bit backlight
0x76e 16 Bit backlight
0x77f edp/dp/hdmi probe? retina only.
* Addition by Bruno Prémont <bonbons@linux-vserver.org>:
"Missing is also precise knowledge as to what the gmux depends on.
From behavioral reports, it is somehow sensitive to VGA IO/MEM
routing (it apparently needs the routing to go to integrated GPU,
not discrete GPU).
When the routing is inappropriate backlight control IO just reads back
as 0xFF (and eventually gmux IO in general does so)."
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/da309e436fbeac886477d80376457b7d83ea4b2d.1452431795.git.lukas@wunner.de
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Add a dummy entry to CEA/HDMI mode tables so they can be indexed
directly using the VIC, avoiding a +1/-1 dance here and there. This adds
clarity to the error checking for various functions that return the VIC
on success and zero on failure; we can now explicitly check for 0
instead of just subtracting one from an unsigned type.
Also add drm_valid_cea_vic() and drm_valid_hdmi_vic() helpers for
checking valid VICs.
v2: add drm_valid_cea_vic and drm_valid_hdmi_vic helpers (Ville)
use { } instead of { 0 } for initializing the dummy modes
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452252111-6439-1-git-send-email-jani.nikula@intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Another pile of vfuncs from the old gpu.tmpl xml documentation that
I've forgotten to delete. I spotted a few more things to
clarify/extend in the new kerneldoc while going through this once
more.
v2: Spelling fixes (Thierry).
v3: More spelling fixes and use Thierry's proposal to clarify why
drivers need to validate modes both in ->mode_fixup and ->mode_valid.
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Thierry Reding <treding@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
The current error path for failure when establishing a handle for a GEM
object is unbalance, e.g. we call object_close() without calling first
object_open(). Use the typical onion structure to only undo what has
been set up prior to the error.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Fix indentation of vga_switcheroo sections in gpu.tmpl.
Change section type of API documentation from "chapter" to "sect1"
so that the individual functions no longer clutter up the ToC.
Group together under a new "API" chapter.
Fix wording "heretoforth" -> "henceforth".
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The drm_dp_mst_topology_cbs structures are never modified, so declare them
as const.
Done with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
pan_display_atomic() calls drm_atomic_clean_old_fb() to sanitize the
legacy FB fields (plane->fb and plane->old_fb). However it was building
the plane mask to pass to this function incorrectly (the bitwise OR was
using plane indices rather than plane masks). The end result was that
sometimes the legacy pointers would become out of sync with the atomic
pointers. If another operation tried to re-set the same FB onto the
plane, we might end up with the pointers back in sync, but improper
reference counts, which would eventually lead to system crashes when we
accessed a pointer to a prematurely-destroyed FB.
The cause here was a very subtle bug introduced in commit:
commit 07d3bad6c1
Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date: Wed Nov 11 11:29:11 2015 +0100
drm/core: Fix old_fb handling in pan_display_atomic.
I found the crashes were most easily reproduced (on i915 at least) by
starting X and then VT switching to a VT that wasn't running a console
instance...the sequence of vt/fbcon entries that happen in that case
trigger a reference count mismatch and crash the system.
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=93313
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drm_dev_set_unique() uses a format string to define the unique name of a
device. This feature is not used as currently all the calls to this
function either use "%s" as a format string or directly use
dev_name().
Even though this second kind of call does not introduce security
problems, because there cannot be "%" characters in dev_name() results,
gcc issues a warning when building with -Wformat-security flag
("warning: format string is not a string literal (potentially
insecure)"). This warning is useful to find real bugs like the one
fixed by commit 3958b79266 ("configfs: fix kernel infoleak through
user-controlled format string"). False positives which do not bring
an extra value make the work of finding real bugs harder.
Therefore remove the format-string feature from drm_dev_set_unique().
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1449829228-4425-1-git-send-email-nicolas.iooss_linux@m4x.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
If the DSI output isn't connected, then mdfld_dsi_encoder_get_pipe()
will return -1. The mdfld_dsi_dp_mode_set() function doesn't properly
check for this condition and causes the following compiler warnings:
CC drivers/gpu/drm/gma500/mdfld_dsi_dpi.o
drivers/gpu/drm/gma500/mdfld_dsi_dpi.c: In function ‘mdfld_dsi_dpi_mode_set’:
drivers/gpu/drm/gma500/mdfld_dsi_dpi.c:828:35: warning: array subscript is below array bounds [-Warray-bounds]
u32 pipeconf = dev_priv->pipeconf[pipe];
^
drivers/gpu/drm/gma500/mdfld_dsi_dpi.c:829:33: warning: array subscript is below array bounds [-Warray-bounds]
u32 dspcntr = dev_priv->dspcntr[pipe];
^
Fix this by checking for a valid pipe before indexing the pipeconf and
dspcntr arrays.
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450178476-26284-2-git-send-email-boris.brezillon@free-electrons.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
