linux.git/drivers/gpu/drm/drm_dp_aux_dev.c, branch v5.8

drm/dp_mst: Add MST support to DP DPCD R/W functions

2020-01-09T23:07:46+00:00

Instead of having drm_dp_dpcd_read/write and
drm_dp_mst_dpcd_read/write as entry points into the
aux code, have drm_dp_dpcd_read/write handle both.

This means that DRM drivers can make MST DPCD read/writes.

v2: Fix spacing
v3: Dump dpcd access on MST read/writes
v4: Fix calling wrong function on DPCD write
v5: delete deprecated include of drmP.h

Reviewed-by: Lyude Paul 
Reviewed-by: Harry Wentland 
Signed-off-by: David Francis 
Signed-off-by: Mikita Lipski 
Signed-off-by: Alex Deucher

drm/dp_mst: Enable registration of AUX devices for MST ports

2019-07-25T20:39:35+00:00

All available downstream ports - physical and logical - are exposed for
each MST device. They are listed in /dev/, following the same naming
scheme as SST devices by appending an incremental ID.

Although all downstream ports are exposed, only some will work as
expected. Consider the following topology:

               +---------+
               |  ASIC   |
               +---------+
              Conn-0|
                    |
               +----v----+
          +----| MST HUB |----+
          |    +---------+    |
          |                   |
          |Port-1       Port-2|
    +-----v-----+       +-----v-----+
    |  MST      |       |  SST      |
    |  Display  |       |  Display  |
    +-----------+       +-----------+
          |Port-1
          x

 MST Path  | MST Device
 ----------+----------------------------------
 sst:0     | MST Hub
 mst:0-1   | MST Display
 mst:0-1-1 | MST Display's disconnected DP out
 mst:0-1-8 | MST Display's internal sink
 mst:0-2   | SST Display

On certain MST displays, the upstream physical port will ACK DPCD reads.
However, reads on the local logical port to the internal sink will
*NAK*. i.e. reading mst:0-1 ACKs, but mst:0-1-8 NAKs.

There may also be duplicates. Some displays will return the same GUID
when reading DPCD from both mst:0-1 and mst:0-1-8.

There are some device-dependent behavior as well. The MST hub used
during testing will actually *ACK* read requests on a disconnected
physical port, whereas the MST displays will NAK.

In light of these discrepancies, it's simpler to expose all downstream
ports - both physical and logical - and let the user decide what to use.

v3 changes:
* Change WARN_ON_ONCE -> DRM_ERROR on dpcd read errors
* Docstring and cosmetic fixes

v2 changes:

Moved remote aux device (un)registration to new mst connector late
register and early unregister helpers. Drivers should call these from
their own mst connector function hooks.

This is to solve an issue during driver unload, where mst connector
devices are unregistered before the remote aux devices are. In a setup
where aux devices are created as children of connector devices, the aux
device would be removed too early, and uncleanly. Doing so in
early_unregister solves this issue, as that is called before connector
unregistration.

Signed-off-by: Ville Syrjälä 
Signed-off-by: Leo Li 
Reviewed-by: Lyude Paul 
Signed-off-by: Harry Wentland 
Link: https://patchwork.freedesktop.org/patch/msgid/20190723232808.28128-3-sunpeng.li@amd.com

drm/dp: Use non-cyclic idr

2019-07-25T20:19:19+00:00

In preparation for adding aux devices for DP MST, make the IDR
non-cyclic. That way, hotplug cycling MST devices won't needlessly
increment the minor version index.

Signed-off-by: Leo Li 
Reviewed-by: Lyude Paul 
Reviewed-by: Ville Syrjälä 
Signed-off-by: Harry Wentland 
Link: https://patchwork.freedesktop.org/patch/msgid/20190723232808.28128-2-sunpeng.li@amd.com

drm/dp: drmP.h include removal

2019-05-06T13:00:48+00:00

Continue to get rid of drmP.h. Add minimal includes to build. Sort
includes while at it.

Reviewed-by: Noralf Trønnes 
Signed-off-by: Jani Nikula 
Link: https://patchwork.freedesktop.org/patch/msgid/20190506095248.20874-1-jani.nikula@intel.com

sched/wait, drivers/drm: Convert wait_on_atomic_t() usage to the new wait_var_event() API

2018-03-20T07:23:18+00:00

The old wait_on_atomic_t() is going to get removed, use the more
flexible wait_var_event() API instead.

Unlike wake_up_atomic_t(), wake_up_var() will issue the wakeup
even if the variable is not 0.

No change in functionality.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Chris Wilson 
Cc: Daniel Vetter 
Cc: David Airlie 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

Pass mode to wait_on_atomic_t() action funcs and provide default actions

2017-11-13T15:38:16+00:00

Make wait_on_atomic_t() pass the TASK_* mode onto its action function as an
extra argument and make it 'unsigned int throughout.

Also, consolidate a bunch of identical action functions into a default
function that can do the appropriate thing for the mode.

Also, change the argument name in the bit_wait*() function declarations to
reflect the fact that it's the mode and not the bit number.

[Peter Z gives this a grudging ACK, but thinks that the whole atomic_t wait
should be done differently, though he's not immediately sure as to how]

Signed-off-by: David Howells 
Acked-by: Peter Zijlstra 
cc: Ingo Molnar

drm_dp_aux_dev: switch to read_iter/write_iter

2017-07-09T00:51:46+00:00

Signed-off-by: Al Viro

drm: Don't export dp-aux devnode functions

2016-08-16T16:49:26+00:00

They're only used internally within the dp helpers. Also nuke the
kerneldoc (we only document the driver interface in the drm shared
functions). And move the header file from the public include/
directory to the source files into drm_crtc_helper_internal.h, similar
to how we already have drm_crtc_internal.h.

While at it also move drm_fb_helper_modinit since that belongs in
there, too.

I noticed this all since I spotted kerneldoc which wasn't pulled into
the rst templates.

v2: Update Copyright date.

Cc: Sean Paul 
Cc: Rafael Antognolli 
Reviewed-by: Sean Paul 
Signed-off-by: Daniel Vetter 
Link: http://patchwork.freedesktop.org/patch/msgid/1471034937-651-16-git-send-email-daniel.vetter@ffwll.ch

drm_aux-dev: fix error handling in drm_dp_aux_dev_init()

2016-07-12T12:10:57+00:00

If class_create() fails, there is no need for class_destroy().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov 
Signed-off-by: Daniel Vetter 
Link: http://patchwork.freedesktop.org/patch/msgid/1467237135-13075-1-git-send-email-khoroshilov@ispras.ru

drm/dp: Allow signals to interrupt drm_aux-dev reads/writes

2016-04-28T09:48:09+00:00

Let's be nice and interrupt the dpcd aux-dev reads/writes when there's
a signal pending. Much nicer if the user can hit ^C instead of having to
sit around waiting for the read/write to finish.

time dd if=/dev/drm_dp_aux0 bs=$((1024*1024))
^C

before:
 real	0m34.681s
 user	0m0.003s
 sys	0m6.880s

after:
 real	0m0.222s
 user	0m0.006s
 sys	0m0.057s

Cc: Rafael Antognolli 
Signed-off-by: Ville Syrjälä 
Reviewed-by: Jani Nikula 
Signed-off-by: Daniel Vetter 
Link: http://patchwork.freedesktop.org/patch/msgid/1461786225-7790-1-git-send-email-ville.syrjala@linux.intel.com