Specifically document the new/clarified rules around how the shared
fences do not have any ordering requirements against the exclusive
fence.
But also document all the things a bit better, given how central
struct dma_resv to dynamic buffer management the docs have been very
inadequat.
- Lots more links to other pieces of the puzzle. Unfortunately
ttm_buffer_object has no docs, so no links :-(
- Explain/complain a bit about dma_resv_locking_ctx(). I still don't
like that one, but fixing the ttm call chains is going to be
horrible. Plus we want to plug in real slowpath locking when we do
that anyway.
- Main part of the patch is some actual docs for struct dma_resv.
Overall I think we still have a lot of bad naming in this area (e.g.
dma_resv.fence is singular, but contains the multiple shared fences),
but I think that's more indicative of how the semantics and rules are
just not great.
Another thing that's real awkard is how chaining exclusive fences
right now means direct dma_resv.exclusive_fence pointer access with an
rcu_assign_pointer. Not so great either.
v2:
- Fix a pile of typos (Matt, Jason)
- Hammer it in that breaking the rules leads to use-after-free issues
around dma-buf sharing (Christian)
Reviewed-by: Christian König <christian.koenig@amd.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-21-daniel.vetter@ffwll.ch
There's only one exclusive slot, and we must not break the ordering.
Adding a new exclusive fence drops all previous fences from the
dma_resv. To avoid violating the signalling order we err on the side of
over-synchronizing by waiting for the existing fences, even if
userspace asked us to ignore them.
A better fix would be to us a dma_fence_chain or _array like e.g.
amdgpu now uses, but
- msm has a synchronous dma_fence_wait for anything from another
context, so doesn't seem to care much,
- and it probably makes sense to lift this into dma-resv.c code as a
proper concept, so that drivers don't have to hack up their own
solution each on their own.
v2: Improve commit message per Lucas' suggestion.
Cc: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-17-daniel.vetter@ffwll.ch
It might be good enough on x86 with just READ_ONCE, but the write side
should then at least be WRITE_ONCE because x86 has total store order.
It's definitely not enough on arm.
Fix this proplery, which means
- explain the need for the barrier in both places
- point at the other side in each comment
Also pull out the !sched_list case as the first check, so that the
code flow is clearer.
While at it sprinkle some comments around because it was very
non-obvious to me what's actually going on here and why.
Note that we really need full barriers here, at first I thought
store-release and load-acquire on ->last_scheduled would be enough,
but we actually requiring ordering between that and the queue state.
v2: Put smp_rmp() in the right place and fix up comment (Andrey)
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210805104705.862416-4-daniel.vetter@ffwll.ch
While unplugging a device the TTM shrinker implementation
needs a barrier to make sure that all concurrent shrink
operations are done and no other CPU is referring to a
device specific pool any more.
Taking and releasing the shrinker semaphore on the write
side after unmapping and freeing all pages from the device
pool should make sure that no shrinker is running in
paralell.
This allows us to avoid the contented mutex in the TTM pool
implementation for every alloc/free operation.
v2: rework the commit message to make clear why we need this
v3: rename the function and add more doc as suggested by Daniel
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Huang Rui <ray.huang@amd.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210820120528.81114-2-christian.koenig@amd.com
Commit 55b68fb856 ("drm/omap: squash omapdrm sub-modules into one")
removes the config OMAP2_DSS in ./drivers/gpu/drm/omapdrm/dss/Kconfig,
while moving the other configs into./drivers/gpu/drm/omapdrm/Kconfig, but
misses to remove an obsolete selection of OMAP2_DSS in config DRM_OMAP.
Hence, ./scripts/checkkconfigsymbols.py warns:
OMAP2_DSS
Referencing files: drivers/gpu/drm/omapdrm/Kconfig
Remove this reference in an obsolete selection.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210819112253.16484-6-lukas.bulwahn@gmail.com
Commit 57692c94dc ("drm/v3d: Introduce a new DRM driver for Broadcom V3D
V3.x+") adds the config DRM_V3D, which depends on "ARCH_BCMSTB".
Although, a bit confusing: all Broadcom architectures in
./arch/arm/mach-bcm/Kconfig have the prefix "ARCH_BCM", except for
ARCH_BRCMSTB, i.e., the config for Broadcom BCM7XXX based boards.
So, correct the reference ARCH_BCMSTB to the intended ARCH_BRCMSTB.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210819112253.16484-4-lukas.bulwahn@gmail.com
Add a new drm_connector_oob_hotplug_event() function and
oob_hotplug_event drm_connector_funcs member.
On some hardware a hotplug event notification may come from outside the
display driver / device. An example of this is some USB Type-C setups
where the hardware muxes the DisplayPort data and aux-lines but does
not pass the altmode HPD status bit to the GPU's DP HPD pin.
In cases like this the new drm_connector_oob_hotplug_event() function can
be used to report these out-of-band events.
Changes in v2:
- Make drm_connector_oob_hotplug_event() take a fwnode as argument and
have it call drm_connector_find_by_fwnode() internally. This allows
making drm_connector_find_by_fwnode() a drm-internal function and
avoids code outside the drm subsystem potentially holding on the
a drm_connector reference for a longer period.
Changes in v3:
- Drop the data argument to the drm_connector_oob_hotplug_event
function since it is not used atm. This can be re-added later when
a use for it actually arises.
Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20210817215201.795062-5-hdegoede@redhat.com
Add a function to find a connector based on a fwnode.
This will be used by the new drm_connector_oob_hotplug_event()
function which is added by the next patch in this patch-set.
Changes in v2:
- Complete rewrite to use a global connector list in drm_connector.c
rather then using a class-dev-iter in drm_sysfs.c
Changes in v3:
- Add forward declaration for struct fwnode_handle to drm_crtc_internal.h
(fixes warning reported by kernel test robot <lkp@intel.com>)
Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20210817215201.795062-4-hdegoede@redhat.com
Add a fwnode pointer to struct drm_connector and register an acpi_bus_type
for the connectors with the ACPI subsystem (when CONFIG_ACPI is enabled).
The adding of the fwnode pointer allows drivers to associate a fwnode
that represents a connector with that connector.
When the new fwnode pointer points to an ACPI-companion, then the new
acpi_bus_type will cause the ACPI subsys to bind the device instantiated
for the connector with the fwnode by calling acpi_bind_one(). This will
result in a firmware_node symlink under /sys/class/card#-<connecter-name>/
which helps to verify that the fwnode-s and connectors are properly
matched.
Changes in v2:
- Make drm_connector_cleanup() call fwnode_handle_put() on
connector->fwnode and document this
Co-developed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20210817215201.795062-3-hdegoede@redhat.com
2 improvements to the Lenovo Ideapad D330 panel-orientation quirks:
1. Some versions of the Lenovo Ideapad D330 have a DMI_PRODUCT_NAME of
"81H3" and others have "81MD". Testing has shown that the "81MD" also has
a 90 degree mounted panel. Drop the DMI_PRODUCT_NAME from the existing
quirk so that the existing quirk matches both variants.
2. Some of the Lenovo Ideapad D330 models have a HD (800x1280) screen
instead of a FHD (1200x1920) screen (both are mounted right-side-up) add
a second Lenovo Ideapad D330 quirk for the HD version.
Changes in v2:
- Add a new quirk for Lenovo Ideapad D330 models with a HD screen instead
of a FHD screen
Link: https://github.com/systemd/systemd/pull/18884
Acked-by: Simon Ser <contact@emersion.fr>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210530110428.12994-2-hdegoede@redhat.com
It is expected from the clients to follow the below steps on an imported
dmabuf fd:
a) dmabuf = dma_buf_get(fd) // Get the dmabuf from fd
b) dma_buf_attach(dmabuf); // Clients attach to the dmabuf
o Here the kernel does some slab allocations, say for
dma_buf_attachment and may be some other slab allocation in the
dmabuf->ops->attach().
c) Client may need to do dma_buf_map_attachment().
d) Accordingly dma_buf_unmap_attachment() should be called.
e) dma_buf_detach () // Clients detach to the dmabuf.
o Here the slab allocations made in b) are freed.
f) dma_buf_put(dmabuf) // Can free the dmabuf if it is the last
reference.
Now say an erroneous client failed at step c) above thus it directly
called dma_buf_put(), step f) above. Considering that it may be the last
reference to the dmabuf, buffer will be freed with pending attachments
left to the dmabuf which can show up as the 'memory leak'. This should
at least be reported as the WARN().
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1627043468-16381-1-git-send-email-charante@codeaurora.org
Signed-off-by: Christian König <christian.koenig@amd.com>
