bochs_fbdev.c is almost empty now. Move the remaining framebuffer bits
over to bochs_kms.c. Pure code motion. No functional change.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190111053752.4004-17-kraxel@redhat.com
Conversion to atomic modesetting, step three.
Wire up atomic helpers. Switch planes to atomic.
We are late to the party, the transitional helpers are gone,
so this can't be splitted into smaller steps any more.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190111053752.4004-6-kraxel@redhat.com
Create a separate bochs_hw_setformat function to configure
the framebuffer format (actually just the byteorder).
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190111053752.4004-3-kraxel@redhat.com
Most unused callbacks can be NULL pointers these days.
Drop a bunch of empty encoder callbacks.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190111053752.4004-2-kraxel@redhat.com
This patch adds the rk3066 VOP definitions.
The VOP or LCD Controller serves as interface between
framebuffer memory and a display device (LCD panel or TV set).
This SOC has two symmetrical LCDC's for a dual panel application.
A LCDC has 5 display layers.
Only 3 are used here.
- Video layer 0 (Win0)
- Video layer 1 (Win1)
- OSD layer (Win2)
Win0 and Win1 are exchangeable.
Maximum resolution is 1920x1080.
The LCDC0 output is connected to:
- LCDC0 IO (without IOMUX)
- HDMI TX video input
The LCDC1 output is connected to:
- LCDC1 IO (with IOMUX)
- HDMI TX video input
The HDMI TX input can switch between LCDC0 and LCDC1.
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20181229133318.18128-4-jbx6244@gmail.com
I noticed a link that didn't work ...
Fixes: 1f2db3034c ("drm: of: introduce drm_of_find_panel_or_bridge")
Cc: Rob Herring <robh@kernel.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111164048.29067-2-daniel.vetter@ffwll.ch
It's not a core function, and the matching atomic functions are also
not in the core. Plus the suspend/resume helper is also already there.
Needs a tiny bit of open-coding, but less midlayer beats that I think.
v2: Rebase onto ast (which gained a new user).
Cc: Sam Bobroff <sbobroff@linux.ibm.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Sean Paul <sean@poorly.run>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "David (ChunMing) Zhou" <David1.Zhou@amd.com>
Cc: Rex Zhu <Rex.Zhu@amd.com>
Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Shaoyun Liu <Shaoyun.Liu@amd.com>
Cc: Monk Liu <Monk.Liu@amd.com>
Cc: nouveau@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20181217194303.14397-4-daniel.vetter@ffwll.ch
The TPO (Toppoly) TPG110 is a pretty generic display driver
similar in vein to the Ilitek 93xx devices. It is not a panel
per se but a driver used with several low-cost noname panels.
This is used on the Nomadik NHK15 combined with a OSD
OSD057VA01CT display for WVGA 800x480.
The driver is pretty minimalistic right now but can be
extended to handle non-default polarities, gamma correction
etc.
The driver is based on the baked-in code in
drivers/video/fbdev/amba-clcd-nomadik.c which will be
decomissioned once this us upstream.
Cc: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111175406.27646-1-linus.walleij@linaro.org
When drivers pass non-empty lists of modifiers for initializing their
planes, we can infer that they allow framebuffer modifiers and set the
driver's allow_fb_modifiers mode config element.
In case the allow_fb_modifiers element was not set (some drivers tend
to set them after registering planes), the modifiers will still be
registered but won't be available to userspace unless the flag is set
later. However in that case, the IN_FORMATS blob won't be created.
In order to avoid this case and generally reduce the trouble associated
with the flag, always set allow_fb_modifiers when a non-empty list of
format modifiers is passed at plane init.
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190104085610.5829-1-paul.kocialkowski@bootlin.com
Despite what the HVS documentation indicates, the VC4 does not actually
support SAND tiling modes for any RGB format and only semiplanar YUV420
formats (NV12/NV21) can be used in these tiling modes.
The driver currently claims to support RGB formats for the associated
modifiers, so remove them from the supported list in the
format_mod_supported helper for RGB formats.
Remove further checks that are no longer necessary along the way, since
semi-planar YUV420 formats support every SAND tiling mode.
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181214141218.12671-1-paul.kocialkowski@bootlin.com
drm-next has been forwarded to 5.0-rc1, and we need it to apply the damage
helper for dirtyfb series from Noralf Trønnes.
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
It's a legacy kms only thing, good to hide it better now that all
those old drivers use the legacy crtc helpers directly.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Link: https://patchwork.freedesktop.org/patch/msgid/20181217194303.14397-3-daniel.vetter@ffwll.ch
The correct way for legacy drivers to update properties that need to
do a full modeset, is to do a full modeset.
Note that we don't need to call the drm_mode_config_internal helper
because we're not changing any of the refcounted paramters.
v2: Fixup error handling (Ville). Since the old code didn't bother
I decided to just delete it instead of adding even more code for just
error handling.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Cc: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181217194303.14397-2-daniel.vetter@ffwll.ch
The correct way for legacy drivers to update properties that need to
do a full modeset, is to do a full modeset.
Note that we don't need to call the drm_mode_config_internal helper
because we're not changing any of the refcounted paramters.
v2: Fixup error handling (Ville). Since the old code didn't bother
I decided to just delete it instead of adding even more code for just
error handling.
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181217194303.14397-1-daniel.vetter@ffwll.ch
Currently, nouveau uses the yolo method of setting up MST displays: it
uses the old VCPI helpers (drm_dp_find_vcpi_slots()) for computing the
display configuration. These helpers don't take care to make sure they
take a reference to the mstb port that they're checking, and
additionally don't actually check whether or not the topology still has
enough bandwidth to provide the VCPI tokens required.
So, drop usage of the old helpers and move entirely over to the atomic
helpers.
Changes since v6:
* Cleanup atomic check logic and remove a bunch of unneeded checks -
danvet
Changes since v5:
* Update nv50_msto_atomic_check() and nv50_mstc_atomic_check() to the
new requirements for drm_dp_atomic_find_vcpi_slots() and
drm_dp_atomic_release_vcpi_slots()
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-21-lyude@redhat.com
It occurred to me that we never actually check this! So let's start
doing that.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-20-lyude@redhat.com
There has been a TODO waiting for quite a long time in
drm_dp_mst_topology.c:
/* We cannot rely on port->vcpi.num_slots to update
* topology_state->avail_slots as the port may not exist if the parent
* branch device was unplugged. This should be fixed by tracking
* per-port slot allocation in drm_dp_mst_topology_state instead of
* depending on the caller to tell us how many slots to release.
*/
That's not the only reason we should fix this: forcing the driver to
track the VCPI allocations throughout a state's atomic check is
error prone, because it means that extra care has to be taken with the
order that drm_dp_atomic_find_vcpi_slots() and
drm_dp_atomic_release_vcpi_slots() are called in in order to ensure
idempotency. Currently the only driver actually using these helpers,
i915, doesn't even do this correctly: multiple ->best_encoder() checks
with i915's current implementation would not be idempotent and would
over-allocate VCPI slots, something I learned trying to implement
fallback retraining in MST.
So: simplify this whole mess, and teach drm_dp_atomic_find_vcpi_slots()
and drm_dp_atomic_release_vcpi_slots() to track the VCPI allocations for
each port. This allows us to ensure idempotency without having to rely
on the driver as much. Additionally: the driver doesn't need to do any
kind of VCPI slot tracking anymore if it doesn't need it for it's own
internal state.
Additionally; this adds a new drm_dp_mst_atomic_check() helper which
must be used by atomic drivers to perform validity checks for the new
VCPI allocations incurred by a state.
Also: update the documentation and make it more obvious that these
/must/ be called by /all/ atomic drivers supporting MST.
Changes since v9:
* Add some missing changes that were requested by danvet that I forgot
about after I redid all of the kref stuff:
* Remove unnecessary state changes in intel_dp_mst_atomic_check
* Cleanup atomic check logic for VCPI allocations - all we need to check in
compute_config is whether or not this state disables a CRTC, then free
VCPI based off that
Changes since v8:
* Fix compile errors, whoops!
Changes since v7:
- Don't check for mixed stale/valid VCPI allocations, just rely on
connector registration to stop such erroneous modesets
Changes since v6:
- Keep a kref to all of the ports we have allocations on. This required
a good bit of changing to when we call drm_dp_find_vcpi_slots(),
mainly that we need to ensure that we only redo VCPI allocations on
actual mode or CRTC changes, not crtc_state->active changes.
Additionally, we no longer take the registration of the DRM connector
for each port into account because so long as we have a kref to the
port in the new or previous atomic state, the connector will stay
registered.
- Use the small changes to drm_dp_put_port() to add even more error
checking to make misusage of the helpers more obvious. I added this
after having to chase down various use-after-free conditions that
started popping up from the new helpers so no one else has to
troubleshoot that.
- Move some accidental DRM_DEBUG_KMS() calls to DRM_DEBUG_ATOMIC()
- Update documentation again, note that find/release() should both not be
called on the same port in a single atomic check phase (but multiple
calls to one or the other is OK)
Changes since v4:
- Don't skip the atomic checks for VCPI allocations if no new VCPI
allocations happen in a state. This makes the next change I'm about
to list here a lot easier to implement.
- Don't ignore VCPI allocations on destroyed ports, instead ensure that
when ports are destroyed and still have VCPI allocations in the
topology state, the only state changes allowed are releasing said
ports' VCPI. This prevents a state with a mix of VCPI allocations
from destroyed ports, and allocations from valid ports.
Changes since v3:
- Don't release VCPI allocations in the topology state immediately in
drm_dp_atomic_release_vcpi_slots(), instead mark them as 0 and skip
over them in drm_dp_mst_duplicate_state(). This makes it so
drm_dp_atomic_release_vcpi_slots() is still idempotent while also
throwing warnings if the driver messes up it's book keeping and tries
to release VCPI slots on a port that doesn't have any pre-existing
VCPI allocation - danvet
- Change mst_state/state in some debugging messages to "mst state"
Changes since v2:
- Use kmemdup() for duplicating MST state - danvet
- Move port validation out of duplicate state callback - danvet
- Handle looping through MST topology states in
drm_dp_mst_atomic_check() so the driver doesn't have to do it
- Fix documentation in drm_dp_atomic_find_vcpi_slots()
- Move the atomic check for each individual topology state into it's
own function, reduces indenting
- Don't consider "stale" MST ports when calculating the bandwidth
requirements. This is needed because originally we relied on the
state duplication functions to prune any stale ports from the new
state, which would prevent us from incorrectly considering their
bandwidth requirements alongside legitimate new payloads.
- Add function references in drm_dp_atomic_release_vcpi_slots() - danvet
- Annotate atomic VCPI and atomic check functions with __must_check
- danvet
Changes since v1:
- Don't use the now-removed ->atomic_check() for private objects hook,
just give drivers a function to call themselves
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-19-lyude@redhat.com
Changes since v6:
- Move EXPORT_SYMBOL() for drm_dp_mst_topology_state_funcs to this
commit
- Document __drm_dp_mst_state_iter_get() and note that it shouldn't be
called directly
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-18-lyude@redhat.com
Going through the currently programmed payloads isn't safe without
holding mgr->payload_lock, so actually do that and warn if anyone tries
calling nv50_msto_payload() in the future without grabbing the right
locks.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-17-lyude@redhat.com
Same as we did for i915, but for nouveau this time. Additionally, we
grab a malloc reference to the port that lasts for the entire lifetime
of nv50_mstc, which gives us the guarantee that mstc->port will always
point to valid memory for as long as the mstc stays around.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-16-lyude@redhat.com
Now that we finally have a sane way to keep port allocations around, use
it to fix the potential unchecked ->port accesses that nouveau makes by
making sure we keep the mst port allocated for as long as it's
drm_connector is accessible.
Additionally, now that we've guaranteed that mstc->port is allocated for
as long as we keep mstc around we can remove the connector registration
checks for codepaths which release payloads, allowing us to release
payloads on active topologies properly. These registration checks were
only required before in order to avoid situations where mstc->port could
technically be pointing at freed memory.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-15-lyude@redhat.com
There is no need to look at the port's VCPI allocation before calling
drm_dp_mst_deallocate_vcpi(), as we already have msto->disabled to let
us avoid cleaning up an msto more then once. The DP MST core will never
call drm_dp_mst_deallocate_vcpi() on it's own, which is presumably what
these checks are meant to protect against.
More importantly though, we're about to stop clearing mstc->port in the
next commit, which means if we could potentially hit a use-after-free
error if we tried to check mstc->port->vcpi here. So to make life easier
for anyone who bisects this code in the future, use msto->disabled
instead to check whether or not we need to deallocate VCPI instead.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-14-lyude@redhat.com
Trying to destroy the connector using mstc->connector.funcs->destroy()
if connector initialization fails is wrong: there is no possible
codepath in nv50_mstc_new where nv50_mstm_add_connector() would return
<0 and mstc would be non-NULL.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-13-lyude@redhat.com
Just like i915 and nouveau, it's a good idea for us to hold a malloc
reference to the port here so that we never pass a freed pointer to any
of the DP MST helper functions.
Also, we stop unsetting aconnector->port in
dm_dp_destroy_mst_connector(). There's literally no point to that
assignment that I can see anyway.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-12-lyude@redhat.com
So that the ports stay around until we've destroyed the connectors, in
order to ensure that we don't pass an invalid pointer to any MST helpers
once we introduce the new MST VCPI helpers.
Changes since v1:
* Move drm_dp_mst_get_port_malloc() to where we assign
intel_connector->port - danvet
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-11-lyude@redhat.com
Up until now, freeing payloads on remote MST hubs that just had ports
removed has almost never worked because we've been relying on port
validation in order to stop us from accessing ports that have already
been freed from memory, but ports which need their payloads released due
to being removed will never be a valid part of the topology after
they've been removed.
Since we've introduced malloc refs, we can replace all of the validation
logic in payload helpers which are used for deallocation with some
well-placed malloc krefs. This ensures that regardless of whether or not
the ports are still valid and in the topology, any port which has an
allocated payload will remain allocated in memory until it's payloads
have been removed - finally allowing us to actually release said
payloads correctly.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-10-lyude@redhat.com
This has never actually worked, and isn't needed anyway: the driver's
always going to try to deallocate VCPI when it tears down the display
that the VCPI belongs to.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-9-lyude@redhat.com
While this isn't a complete fix, this will improve the reliability of
drm_dp_get_last_connected_port_and_mstb() pretty significantly during
hotplug events, since there's a chance that the in-memory topology tree
may not be fully updated when drm_dp_get_last_connected_port_and_mstb()
is called and thus might end up causing our search to fail on an mstb
whose topology refcount has reached 0, but has not yet been removed from
it's parent.
Ideally, we should further fix this problem by ensuring that we deal
with the potential for racing with a hotplug event, which would look
like this:
* drm_dp_payload_send_msg() retrieves the last living relative of mstb
with drm_dp_get_last_connected_port_and_mstb()
* drm_dp_payload_send_msg() starts building payload message
At the same time, mstb gets unplugged from the topology and is no
longer the actual last living relative of the original mstb
* drm_dp_payload_send_msg() tries sending the payload message, hub times
out
* Hub timed out, we give up and run away-resulting in the payload being
leaked
This could be fixed by restarting the
drm_dp_get_last_connected_port_and_mstb() search whenever we get a
timeout, sending the payload to the new mstb, then repeating until
either the entire topology is removed from the system or
drm_dp_get_last_connected_port_and_mstb() fails. But since the above
race condition is not terribly likely, we'll address that in a later
patch series once we've improved the recovery handling for VCPI
allocations in the rest of the DP MST helpers.
Changes since v1:
* Convert kerneldoc for drm_dp_get_last_connected_port_and_mstb to
normal comment - danvet
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-8-lyude@redhat.com
The current way of handling refcounting in the DP MST helpers is really
confusing and probably just plain wrong because it's been hacked up many
times over the years without anyone actually going over the code and
seeing if things could be simplified.
To the best of my understanding, the current scheme works like this:
drm_dp_mst_port and drm_dp_mst_branch both have a single refcount. When
this refcount hits 0 for either of the two, they're removed from the
topology state, but not immediately freed. Both ports and branch devices
will reinitialize their kref once it's hit 0 before actually destroying
themselves. The intended purpose behind this is so that we can avoid
problems like not being able to free a remote payload that might still
be active, due to us having removed all of the port/branch device
structures in memory, as per:
commit 91a25e4631 ("drm/dp/mst: deallocate payload on port destruction")
Which may have worked, but then it caused use-after-free errors. Being
new to MST at the time, I tried fixing it;
commit 263efde31f ("drm/dp/mst: Get validated port ref in drm_dp_update_payload_part1()")
But, that was broken: both drm_dp_mst_port and drm_dp_mst_branch structs
are validated in almost every DP MST helper function. Simply put, this
means we go through the topology and try to see if the given
drm_dp_mst_branch or drm_dp_mst_port is still attached to something
before trying to use it in order to avoid dereferencing freed memory
(something that has happened a LOT in the past with this library).
Because of this it doesn't actually matter whether or not we keep keep
the ports and branches around in memory as that's not enough, because
any function that validates the branches and ports passed to it will
still reject them anyway since they're no longer in the topology
structure. So, use-after-free errors were fixed but payload deallocation
was completely broken.
Two years later, AMD informed me about this issue and I attempted to
come up with a temporary fix, pending a long-overdue cleanup of this
library:
commit c54c7374ff ("drm/dp_mst: Skip validating ports during destruction, just ref")
But then that introduced use-after-free errors, so I quickly reverted
it:
commit 9765635b30 ("Revert "drm/dp_mst: Skip validating ports during destruction, just ref"")
And in the process, learned that there is just no simple fix for this:
the design is just broken. Unfortunately, the usage of these helpers are
quite broken as well. Some drivers like i915 have been smart enough to
avoid accessing any kind of information from MST port structures, but
others like nouveau have assumed, understandably so, that
drm_dp_mst_port structures are normal and can just be accessed at any
time without worrying about use-after-free errors.
After a lot of discussion, me and Daniel Vetter came up with a better
idea to replace all of this.
To summarize, since this is documented far more indepth in the
documentation this patch introduces, we make it so that drm_dp_mst_port
and drm_dp_mst_branch structures have two different classes of
refcounts: topology_kref, and malloc_kref. topology_kref corresponds to
the lifetime of the given drm_dp_mst_port or drm_dp_mst_branch in it's
given topology. Once it hits zero, any associated connectors are removed
and the branch or port can no longer be validated. malloc_kref
corresponds to the lifetime of the memory allocation for the actual
structure, and will always be non-zero so long as the topology_kref is
non-zero. This gives us a way to allow callers to hold onto port and
branch device structures past their topology lifetime, and dramatically
simplifies the lifetimes of both structures. This also finally fixes the
port deallocation problem, properly.
Additionally: since this now means that we can keep ports and branch
devices allocated in memory for however long we need, we no longer need
a significant amount of the port validation that we currently do.
Additionally, there is one last scenario that this fixes, which couldn't
have been fixed properly beforehand:
- CPU1 unrefs port from topology (refcount 1->0)
- CPU2 refs port in topology(refcount 0->1)
Since we now can guarantee memory safety for ports and branches
as-needed, we also can make our main reference counting functions fix
this problem by using kref_get_unless_zero() internally so that topology
refcounts can only ever reach 0 once.
Changes since v4:
* Change the kernel-figure summary for dp-mst/topology-figure-1.dot a
bit - danvet
* Remove figure numbers - danvet
Changes since v3:
* Remove rebase detritus - danvet
* Split out purely style changes into separate patches - hwentlan
Changes since v2:
* Fix commit message - checkpatch
* s/)-1/) - 1/g - checkpatch
Changes since v1:
* Remove forward declarations - danvet
* Move "Branch device and port refcounting" section from documentation
into kernel-doc comments - danvet
* Export internal topology lifetime functions into their own section in
the kernel-docs - danvet
* s/@/&/g for struct references in kernel-docs - danvet
* Drop the "when they are no longer being used" bits from the kernel
docs - danvet
* Modify diagrams to show how the DRM driver interacts with the topology
and payloads - danvet
* Make suggested documentation changes for
drm_dp_mst_topology_get_mstb() and drm_dp_mst_topology_get_port() -
danvet
* Better explain the relationship between malloc refs and topology krefs
in the documentation for drm_dp_mst_topology_get_port() and
drm_dp_mst_topology_get_mstb() - danvet
* Fix "See also" in drm_dp_mst_topology_get_mstb() - danvet
* Rename drm_dp_mst_topology_get_(port|mstb)() ->
drm_dp_mst_topology_try_get_(port|mstb)() and
drm_dp_mst_topology_ref_(port|mstb)() ->
drm_dp_mst_topology_get_(port|mstb)() - danvet
* s/should/must in docs - danvet
* WARN_ON(refcount == 0) in topology_get_(mstb|port) - danvet
* Move kdocs for mstb/port structs inline - danvet
* Split drm_dp_get_last_connected_port_and_mstb() changes into their own
commit - danvet
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-7-lyude@redhat.com
s/drm_dp_get_validated_port_ref/drm_dp_mst_topology_get_port_validated/
s/drm_dp_put_port/drm_dp_mst_topology_put_port/
s/drm_dp_get_validated_mstb_ref/drm_dp_mst_topology_get_mstb_validated/
s/drm_dp_put_mst_branch_device/drm_dp_mst_topology_put_mstb/
This is a much more consistent naming scheme, and will make even more
sense once we redesign how the current refcounting scheme here works.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-6-lyude@redhat.com
Split some stuff across multiple lines
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@redhat.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: Juston Li <juston.li@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190111005343.17443-5-lyude@redhat.com
