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
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
drm-misc-next for 5.1:
UAPI Changes:
Cross-subsystem Changes:
- Turn dma-buf fence sequence numbers into 64 bit numbers
Core Changes:
- Move to a common helper for the DP MST hotplug for radeon, i915 and
amdgpu
- i2c improvements for drm_dp_mst
- Removal of drm_syncobj_cb
- Introduction of an helper to create and attach the TV margin properties
Driver Changes:
- Improve cache flushes for v3d
- Reflection support for vc4
- HDMI overscan support for vc4
- Add implicit fencing support for rockchip and sun4i
- Switch to generic fbdev emulation for virtio
Signed-off-by: Dave Airlie <airlied@redhat.com>
[airlied: applied amdgpu merge fixup]
From: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190107180333.amklwycudbsub3s5@flea
Generally catch up with 5.0-rc1, and specifically get the changes:
96d4f267e4 ("Remove 'type' argument from access_ok() function")
0b2c8f8b6b ("i915: fix missing user_access_end() in page fault exception case")
594cc251fd ("make 'user_access_begin()' do 'access_ok()'")
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Make some drm headers self-contained with includes and forward
declarations.
This topic branch has already been merged to drm-misc-next as commit
1c95f662fc ("Merge tag 'topic/drmp-cleanup-2019-01-02' of
git://anongit.freedesktop.org/drm/drm-intel into drm-misc-next"). Now
merge it to drm-intel-next-queued to unblock some further drmP.h cleanup
without having to wait for a backmerge.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
From: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/87pntfl6pa.fsf@intel.com
[airlied: make etnaviv build again]
amdgpu:
- DC trace support
- More DC documentation
- XGMI hive reset support
- Rework IH interaction with KFD
- Misc fixes and cleanups
- Powerplay updates for newer polaris variants
- Add cursor plane update fast path
- Enable gpu reset by default on CI parts
- Fix config with KFD/HSA not enabled
amdkfd:
- Limit vram overcommit
- dmabuf support
- Support for doorbell BOs
ttm:
- Support for simultaneous submissions to multiple engines
scheduler:
- Add helpers for hw with preemption support
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181207233119.16861-1-alexander.deucher@amd.com
Final changes to drm-misc-next for v4.21:
UAPI Changes:
Core Changes:
- Add dma_fence_get_stub to dma-buf, and use it in drm/syncobj.
- Add and use DRM_MODESET_LOCK_BEGIN/END helpers.
- Small fixes to drm_atomic_helper_resume(), drm_mode_setcrtc() and
drm_atomic_helper_commit_duplicated_state()
- Fix drm_atomic_state_helper.[c] extraction.
Driver Changes:
- Small fixes to tinydrm, vkms, meson, rcar-du, virtio, vkms,
v3d, and pl111.
- vc4: Allow scaling and YUV formats on cursor planes.
- v3d: Enable use of the Texture Formatting Unit, and fix
prime imports of buffers from other drivers.
- Add support for the AUO G101EVN010 panel.
- sun4i: Enable support for the H6 display engine.
Signed-off-by: Dave Airlie <airlied@redhat.com>
[airlied: added drm/v3d: fix broken build to the merge commit]
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/321be9d3-ab75-5f92-8193-e5113662edef@linux.intel.com
amdgpu and amdkfd:
- Freesync support
- ABM support in DC
- KFD support for vega12 and polaris12
- Add sdma paging queue support for vega
- Use ACPI to query backlight range on supported platforms
- Clean up doorbell handling
- KFD fix for pasid handling under non-HWS
- Misc cleanups and fixes
scheduler:
- Revert "fix timeout handling v2"
radeon:
- Fix possible overflow on 32 bit
ttm:
- Fix for LRU handling for ghost objects
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181130192505.2946-1-alexander.deucher@amd.com
This patch adds two new functions to help client drivers suspend and
resume the scheduler job timeout. This can be useful in cases where the
hardware has preemption support enabled. Using this, it is possible to have
the timeout active only for the ring which is active on the ringbuffer.
This patch also makes the job_list_lock IRQ safe.
Suggested-by: Christian Koenig <Christian.Koenig@amd.com>
Signed-off-by: Sharat Masetty <smasetty@codeaurora.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This reverts commit 9a09a42369.
The whole interface isn't thought through. Since this function can't
fail we actually can't allocate an object to store the sync point.
Sorry, I should have taken the lead on this from the very beginning and
reviewed it more thoughtfully. Going to propose a new interface as a
follow up change.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Link: https://patchwork.freedesktop.org/patch/265580/
Add an atomic helper to implement dirtyfb support. This is needed to
support DSI command-mode panels with x11 userspace (ie. when we can't
rely on pageflips to trigger a flush to the panel).
v2: Modified the helper to use plane fb_damage_clips property and
removed plane_state::dirty flag.
v3:
- Use uapi drm_mode_rect.
- Support annotate flags.
v4: Correct kernel doc.
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
With fb_damage_clips blob property in drm_plane_state, this patch adds
helper iterator to traverse the damage clips that lie inside plane src.
Iterator will return full plane src as damage in case need full plane
update or damage is not specified.
v2:
- Plane src clipping correction
- Handle no plane update case in iter_next
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
FB_DAMAGE_CLIPS is an optional plane property to mark damaged regions
on the plane in framebuffer coordinates of the framebuffer attached to
the plane.
The layout of blob data is simply an array of "struct drm_mode_rect".
Unlike plane src coordinates, damage clips are not in 16.16 fixed point.
As plane src in framebuffer cannot be negative so are damage clips. In
damage clip, x1/y1 are inclusive and x2/y2 are exclusive.
This patch also exports the kernel internal drm_rect to userspace as
drm_mode_rect. This is because "struct drm_clip_rect" is not sufficient
to represent damage for current plane size.
Driver which are interested in enabling FB_DAMAGE_CLIPS property for a
plane should enable this property using drm_plane_enable_damage_clips.
v2:
- Input validation on damage clips against framebuffer size.
- Doc update, other minor changes.
Signed-off-by: Lukasz Spintzyk <lukasz.spintzyk@displaylink.com>
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
This patch adds a couple of helpers to remove the boilerplate involved
in grabbing all of the modeset locks.
I've also converted the obvious cases in drm core to use the helpers.
The only remaining instance of drm_modeset_lock_all_ctx() is in
drm_framebuffer. It's complicated by the state clear that occurs on
deadlock. ATM, there's no way to inject code in the deadlock path with
the helpers, so it's unfit for conversion.
Changes in v2:
- Relocate ret argument to the end of the list (Daniel)
- Incorporate Daniel's doc suggestions (Daniel)
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181129150423.239081-4-sean@poorly.run
drm-misc-next for v4.21:
Core Changes:
- Merge drm_info.c into drm_debugfs.c
- Complete the fake drm_crtc_commit's hw_done/flip_done sooner.
- Remove deprecated drm_obj_ref/unref functions. All drivers use get/put now.
- Decrease stack use of drm_gem_prime_mmap.
- Improve documentation for dumb callbacks.
Driver Changes:
- Add edid support to virtio.
- Wait on implicit fence in meson and sun4i.
- Add support for BGRX8888 to sun4i.
- Preparation patches for sun4i driver to start supporting linear and tiled YUV formats.
- Add support for HDMI 1.4 4k modes to meson, and support for VIC alternate timings.
- Drop custom dumb_map in vkms.
- Small fixes and cleanups to v3d.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/151a3270-b1be-ed75-bd58-6b29d741f592@linux.intel.com
This patch introduces the 'vrr_enabled' CRTC property to allow
dynamic control over variable refresh rate support for a CRTC.
This property should be treated like a content hint to the driver -
if the hardware or driver is not capable of driving variable refresh
timings then this is not considered an error.
Capability for variable refresh rate support should be determined
by querying the vrr_capable drm connector property.
It is worth noting that while the property is intended for atomic use
it isn't filtered from legacy userspace queries. This allows for Xorg
userspace drivers to implement support.
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
