Recently, a few races have been discovered in the GEM LRU logic, all
of them caused by the fact the LRU lock is accessed through
gem->lru->lock, and that very same lock also protects changes to
gem->lru, leading to situations where gem->lru needs to first be
accessed without the lock held, to then get the lru to access the lock
through and finally take the lock and do the expected operation.
Currently, the only driver making use of this API (MSM) declares a
device-wide lock, and the user we're about to add (panthor) will
do the same. There's no evidence that we will ever have a driver
that wants different pools of LRUs protected by different locks under
the same drm_device. So we're better off moving this lock to drm_device
and always locking it through obj->dev->gem_lru_mutex, or directly
through dev->gem_lru_mutex.
If anyone ever needs more fine-grained locking, this can be revisited
to pass some drm_gem_lru_pool object representing the pool of LRUs
under a specific lock, but for now, the per-device lock seems to be
enough.
Fixes: e7c2af13f8 ("drm/gem: Add LRU/shrinker helper")
Reported-by: Chia-I Wu <olvaffe@gmail.com>
Closes: https://gitlab.freedesktop.org/panfrost/linux/-/work_items/86
Reviewed-by: Rob Clark <rob.clark@oss.qualcomm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Link: https://patch.msgid.link/20260518-panthor-shrinker-fixes-v4-1-1920234470d5@collabora.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Add the drm_gem_huge_mnt_create() and drm_gem_get_huge_mnt() helpers
to avoid code duplication in the i915, V3D, Panfrost and Panthor
drivers. The former creates and mounts a dedicated huge tmpfs
mountpoint, for the lifetime of a DRM device, used at GEM object
initialization. The latter retrieves the dedicated huge tmpfs
mountpoint used by a DRM device.
The next commits will port drivers to these helpers.
v3:
- store huge tmpfs mountpoint in drm_device
v4:
- return 0 in builds with CONFIG_TRANSPARENT_HUGEPAGE=n
- return 0 when huge_mnt already exists
- use new vfs_parse_fs_string() helper
v5:
- remove warning on !dev->huge_mnt and reset to NULL on free
- inline drm_gem_huge_mnt_create() to remove func from text and avoid
calls in builds with CONFIG_TRANSPARENT_HUGEPAGE=n
- compile out drm_device's huge_mnt field in builds with
CONFIG_TRANSPARENT_HUGEPAGE=n
- add drm_gem_has_huge_mnt() helper
v6:
- move huge_mnt doc into ifdef'd section
- either inline or export drm_gem_huge_mnt_create()
v7:
- include <drm/drm_device.h> in drm_gem.h
v9:
- replace drm_gem_has_huge_mnt() by drm_gem_get_huge_mnt()
v11:
- doc fixes
- add Boris and Maíra R-bs
Signed-off-by: Loïc Molinari <loic.molinari@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Link: https://patch.msgid.link/20251205182231.194072-5-loic.molinari@collabora.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Move the sysrq functionality from DRM fbdev helpers to the DRM device
and in-kernel clients, so that it becomes available on all clients.
DRM fbdev helpers support emergency restoration of the console output
via a special key combination. Press SysRq+v to replace the current
compositor with the kernel's output on the framebuffer console. This
allows users to see the log messages during system emergencies.
By moving the functionality from fbdev helpers to the DRM device, any
in-kernel client can serve as emergency output. This can be used to
bring up drm_log, for example.
Each DRM device registers itself to the list of possible sysrq handlers.
On receiving SysRq+v, the DRM core goes over all registered devices and
restores an in-kernel DRM client for each of them.
See Documentation/admin-guide/sysrq.rst on how to invoke SysRq. Switch
VTs to bring back the user-space compositor.
v2:
- declare placeholders as 'static inline' (kernel test robot)
- fix grammar in commit description
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patch.msgid.link/20251110154616.539328-3-tzimmermann@suse.de
Address the need for a recovery method (firmware flash on Firmware errors)
introduced in the later patches of Xe KMD.
Whenever XE KMD detects a firmware error, a firmware flash is required to
recover the device to normal operation.
The initial proposal to use 'firmware-flash' as a recovery method was
not applicable to other drivers and could cause multiple recovery
methods specific to vendors to be added.
To address this a more generic 'vendor-specific' method is introduced,
guiding users to refer to vendor specific documentation and system logs
for detailed vendor specific recovery procedure.
Add a recovery method 'WEDGED=vendor-specific' for such errors.
Vendors must provide additional recovery documentation if this method
is used.
It is the responsibility of the consumer to refer to the correct vendor
specific documentation and usecase before attempting a recovery.
For example: If driver is XE KMD, the consumer must refer
to the documentation of 'Device Wedging' under 'Documentation/gpu/xe/'.
v2: fix documentation (Raag)
v3: add more details to commit message (Sima, Rodrigo, Raag)
add an example script to the documentation (Raag)
v4: use consistent naming (Raag)
v5: fix commit message
v6: add more documentation
Cc: André Almeida <andrealmeid@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Cc: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Riana Tauro <riana.tauro@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250826063419.3022216-3-riana.tauro@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
When a device get wedged, it might be caused by a guilty application.
For userspace, knowing which task was involved can be useful for some
situations, like for implementing a policy, logs or for giving a chance
for the compositor to let the user know what task was involved in the
problem. This is an optional argument, when the task info is not
available, the PID and TASK string won't appear in the event string.
Sometimes just the PID isn't enough giving that the task might be already
dead by the time userspace will try to check what was this PID's name,
so to make the life easier also notify what's the task's name in the user
event.
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>
Reviewed-by: Raag Jadav <raag.jadav@intel.com>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/r/20250617124949.2151549-4-andrealmeid@igalia.com
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Importing dma-bufs via PRIME requires a DMA-capable device. Devices on
peripheral busses, such as USB, often cannot perform DMA by themselves.
Without DMA-capable device PRIME import fails. DRM drivers for USB
devices already use a separate DMA device for dma-buf imports. Make the
mechanism generally available.
Besides the case of USB, there are embedded DRM devices without DMA
capability. DMA is performed by a separate controller. DRM drivers should
set this accordingly.
Add the field dma_dev to struct drm_device to refer to the device's DMA
device. For USB this should be the USB controller. Use dma_dev in the
PRIME import helpers, if set.
v2:
- acquire internal reference on dma_dev (Jani)
- add DMA-controller usecase to docs (Maxime)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250307080836.42848-2-tzimmermann@suse.de
Introduce device wedged event, which notifies userspace of 'wedged'
(hanged/unusable) state of the DRM device through a uevent. This is
useful especially in cases where the device is no longer operating as
expected and has become unrecoverable from driver context. Purpose of
this implementation is to provide drivers a generic way to recover the
device with the help of userspace intervention without taking any drastic
measures (like resetting or re-enumerating the full bus, on which the
underlying physical device is sitting) in the driver.
A 'wedged' device is basically a device that is declared dead by the
driver after exhausting all possible attempts to recover it from driver
context. The uevent is the notification that is sent to userspace along
with a hint about what could possibly be attempted to recover the device
from userspace and bring it back to usable state. Different drivers may
have different ideas of a 'wedged' device depending on hardware
implementation of the underlying physical device, and hence the vendor
agnostic nature of the event. It is up to the drivers to decide when they
see the need for device recovery and how they want to recover from the
available methods.
Driver prerequisites
--------------------
The driver, before opting for recovery, needs to make sure that the
'wedged' device doesn't harm the system as a whole by taking care of the
prerequisites. Necessary actions must include disabling DMA to system
memory as well as any communication channels with other devices. Further,
the driver must ensure that all dma_fences are signalled and any device
state that the core kernel might depend on is cleaned up. All existing
mmaps should be invalidated and page faults should be redirected to a
dummy page. Once the event is sent, the device must be kept in 'wedged'
state until the recovery is performed. New accesses to the device
(IOCTLs) should be rejected, preferably with an error code that resembles
the type of failure the device has encountered. This will signify the
reason for wedging, which can be reported to the application if needed.
Recovery
--------
Current implementation defines three recovery methods, out of which,
drivers can use any one, multiple or none. Method(s) of choice will be
sent in the uevent environment as ``WEDGED=<method1>[,..,<methodN>]`` in
order of less to more side-effects. If driver is unsure about recovery
or method is unknown (like soft/hard system reboot, firmware flashing,
physical device replacement or any other procedure which can't be
attempted on the fly), ``WEDGED=unknown`` will be sent instead.
Userspace consumers can parse this event and attempt recovery as per the
following expectations.
=============== ========================================
Recovery method Consumer expectations
=============== ========================================
none optional telemetry collection
rebind unbind + bind driver
bus-reset unbind + bus reset/re-enumeration + bind
unknown consumer policy
=============== ========================================
The only exception to this is ``WEDGED=none``, which signifies that the
device was temporarily 'wedged' at some point but was recovered from driver
context using device specific methods like reset. No explicit recovery is
expected from the consumer in this case, but it can still take additional
steps like gathering telemetry information (devcoredump, syslog). This is
useful because the first hang is usually the most critical one which can
result in consequential hangs or complete wedging.
Consumer prerequisites
----------------------
It is the responsibility of the consumer to make sure that the device or
its resources are not in use by any process before attempting recovery.
With IOCTLs erroring out, all device memory should be unmapped and file
descriptors should be closed to prevent leaks or undefined behaviour. The
idea here is to clear the device of all user context beforehand and set
the stage for a clean recovery.
Example
-------
Udev rule::
SUBSYSTEM=="drm", ENV{WEDGED}=="rebind", DEVPATH=="*/drm/card[0-9]",
RUN+="/path/to/rebind.sh $env{DEVPATH}"
Recovery script::
#!/bin/sh
DEVPATH=$(readlink -f /sys/$1/device)
DEVICE=$(basename $DEVPATH)
DRIVER=$(readlink -f $DEVPATH/driver)
echo -n $DEVICE > $DRIVER/unbind
echo -n $DEVICE > $DRIVER/bind
Customization
-------------
Although basic recovery is possible with a simple script, consumers can
define custom policies around recovery. For example, if the driver supports
multiple recovery methods, consumers can opt for the suitable one depending
on scenarios like repeat offences or vendor specific failures. Consumers
can also choose to have the device available for debugging or telemetry
collection and base their recovery decision on the findings. This is useful
especially when the driver is unsure about recovery or method is unknown.
v4: s/drm_dev_wedged/drm_dev_wedged_event
Use drm_info() (Jani)
Kernel doc adjustment (Aravind)
v5: Send recovery method with uevent (Lina)
v6: Access wedge_recovery_opts[] using helper function (Jani)
Use snprintf() (Jani)
v7: Convert recovery helpers into regular functions (Andy, Jani)
Aesthetic adjustments (Andy)
Handle invalid recovery method
v8: Allow sending multiple methods with uevent (Lucas, Michal)
static_assert() globally (Andy)
v9: Provide 'none' method for device reset (Christian)
Provide recovery opts using switch cases
v11: Log device reset (André)
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250204070528.1919158-2-raag.jadav@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
We would like to be able to enable vblank_disable_immediate
unconditionally, however there are a handful of cases where a small off
delay is necessary (e.g. with PSR enabled). So, we would like to be able
to adjust the vblank off delay and disable imminent values dynamically
for a given CRTC. Since, it will allow drivers to apply static screen
optimizations more quickly and consequently allow users to benefit more
so from the power savings afforded by the aforementioned optimizations,
while avoiding issues in cases where an off delay is still warranted.
In particular, the PSR case requires a small off delay of 2 frames,
otherwise display firmware isn't able to keep up with all of the
requests made to amdgpu. So, introduce drm_crtc_vblank_on_config() which
is like drm_crtc_vblank_on(), but it allows drivers to specify the
vblank CRTC configuration before enabling vblanking support for a given
CRTC.
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20240725205109.209743-1-hamza.mahfooz@amd.com
The mutex was completely pointless in the first place since any
parallel adding of files to this list would result in random
behavior since the list is filled and consumed multiple times.
Completely drop that approach and just create the files directly but
return -ENODEV while opening the file when the minors are not
registered yet.
v2: rebase on debugfs directory rework, limit access before minors are
registered.
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829110115.3442-5-christian.koenig@amd.com
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Instead of the per minor directories only create a single debugfs
directory for the whole device directly when the device is initialized.
For DRM devices each minor gets a symlink to the per device directory
for now until we can be sure that this isn't useful any more in any way.
Accel devices create only the per device directory and also drops the mid
layer callback to create driver specific files.
v2: cleanup accel component as well
v3: fix typo when debugfs is disabled
v4: call drm_debugfs_dev_fini() during release as well,
some kerneldoc typos fixed
v5: rebased and one more kerneldoc fix
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829110115.3442-4-christian.koenig@amd.com
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
drm-misc-next for v6.3:
UAPI Changes:
* fourcc: Document Open Source user waiver
Cross-subsystem Changes:
* firmware: fix color-format selection for system framebuffers
Core Changes:
* format-helper: Add conversion from XRGB8888 to various sysfb formats;
Make XRGB8888 the only driver-emulated legacy format
* fb-helper: Avoid blank consoles from selecting an incorrect color format
* probe-helper: Enable/disable HPD on connectors plus driver updates
* Use drm_dbg_ helpers in several places
* docs: Document defaults for CRTC backgrounds; Document use of drm_minor
Driver Changes:
* arm/hdlcd: Use new debugfs helpers
* gud: Use new debugfs helpers
* panel: Support Visionox VTDR6130 AMOLED DSI; Support Himax HX8394; Convert
many drivers to common generic DSI write-sequence helper
* v3d: Do not opencode drm_gem_object_lookup()
* vc4: Various HVS an CRTC fixes
* vkms: Fix SEGFAULT from incorrect GEM-buffer mapping
* Convert various drivers to i2c probe_new()
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/Y8ADeSzZDj+tpibF@linux-uq9g
The documentation for struct drm_minor already states this, but that's
not always that easy to find.
Also due to historical reasons we still have the minor-centric
interfaces (like drm_debugfs_create_files), but since this is now
getting fixed we can put a few more pointers in place as to how this
should be done ideally. Note that debugfs isn't there yet for all
cases (debugfs files on kms objects like crtc/connector aren't
supported, neither debugfs files with full fops), so the debugfs side
of this is still rather aspirational and more for new users than
converting everything existing. todo.rst covers the additional work
needed already.
Motivated by some discussion with Rodrigo on irc about how drm/xe
should lay out its sysfs interfaces.
v2: Make the debugfs situation clearer in the commit message, but
don't elaborate more in the actual kerneldoc to avoid distracting from
the main message around sysfs (Jani)
Also fix some typos.
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Acked-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Wambui Karuga <wambui.karugax@gmail.com>
Cc: Maíra Canal <mcanal@igalia.com>
Cc: Maxime Ripard <maxime@cerno.tech>
Cc: Melissa Wen <mwen@igalia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230109164604.3860862-1-daniel.vetter@ffwll.ch
drm-misc-next for v6.3:
UAPI Changes:
* connector: Support analog-TV mode property
* media: Add MEDIA_BUS_FMT_RGB565_1X24_CPADHI,
MEDIA_BUS_FMT_RGB666_1X18 and MEDIA_BUS_FMT_RGB666_1X24_CPADHI
Cross-subsystem Changes:
* dma-buf: Documentation fixes
* i2c: Introduce i2c_client_get_device_id() helper
Core Changes:
* Improve support for analog TV output
* bridge: Remove unused drm_bridge_chain functions
* debugfs: Add per-device helpers and convert various DRM drivers
* dp-mst: Various fixes
* fbdev emulation: Always pick 32 bpp as default
* KUnit: Add tests for managed helpers; Various cleanups
* panel-orientation: Add quirks for Lenovo Yoga Tab 3 X90F and DynaBook K50
* TTM: Open-code ttm_bo_wait() and remove the helper
Driver Changes:
* Fix preferred depth and bpp values throughout DRM drivers
* Remove #CONFIG_PM guards throughout DRM drivers
* ast: Various fixes
* bridge: Implement i2c's probe_new in various drivers; Fixes; ite-it6505:
Locking fixes, Cache EDID data; ite-it66121: Support IT6610 chip,
Cleanups; lontium-tl9611: Fix HDMI on DragonBoard 845c; parade-ps8640:
Use atomic bridge functions
* gud: Convert to DRM shadow-plane helpers; Perform flushing synchronously
during atomic update
* ili9486: Support 16-bit pixel data
* imx: Split off IPUv3 driver; Various fixes
* mipi-dbi: Convert to DRM shadow-plane helpers plus rsp driver changes;i
Support separate I/O-voltage supply
* mxsfb: Depend on ARCH_MXS or ARCH_MXC
* omapdrm: Various fixes
* panel: Use ktime_get_boottime() to measure power-down delay in various
drivers; Fix auto-suspend delay in various drivers; orisetech-ota5601a:
Add support
* sprd: Cleanups
* sun4i: Convert to new TV-mode property
* tidss: Various fixes
* v3d: Various fixes
* vc4: Convert to new TV-mode property; Support Kunit tests; Cleanups;
dpi: Support RGB565 and RGB666 formats; dsi: Convert DSI driver to
bridge
* virtio: Improve tracing
* vkms: Support small cursors in IGT tests; Various fixes
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/Y7QIwlfElAYWxRcR@linux-uq9g
The accelerator devices are exposed to user-space using a dedicated
major. In addition, they are represented in /dev with new, dedicated
device char names: /dev/accel/accel*. This is done to make sure any
user-space software that tries to open a graphic card won't open
the accelerator device by mistake.
The above implies that the minor numbering should be separated from
the rest of the DRM devices. However, to avoid code duplication, we
want the drm_minor structure to be able to represent the accelerator
device.
To achieve this, we add a new drm_minor* to drm_device that represents
the accelerator device. This pointer is initialized for drivers that
declare they handle compute accelerator, using a new driver feature
flag called DRIVER_COMPUTE_ACCEL. It is important to note that this
driver feature is mutually exclusive with DRIVER_RENDER. Devices that
want to expose both graphics and compute device char files should be
handled by two drivers that are connected using the auxiliary bus
framework.
In addition, we define a different IDR to handle the accelerators
minors. This is done to make the minor's index be identical to the
device index in /dev/. Any access to the IDR is done solely
by functions in accel_drv.c, as the IDR is define as static. The
DRM core functions call those functions in case they detect the minor's
type is DRM_MINOR_ACCEL.
We define a separate accel_open function (from drm_open) that the
accel drivers should set as their open callback function. Both these
functions eventually call the same drm_open_helper(), which had to be
changed to be non-static so it can be called from accel_drv.c.
accel_open() only partially duplicates drm_open as I removed some code
from it that handles legacy devices.
To help new drivers, I defined DEFINE_DRM_ACCEL_FOPS macro to easily
set the required function operations pointers structure.
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Tested-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Boris Brezillon
Loïc MolinariandBoris Brezillon
Thomas Zimmermann
Rodrigo Vivi
Luiz Otavio MelloandRodrigo Vivi
Riana TauroandRodrigo Vivi
André Almeida
Raag JadavandRodrigo Vivi
Hamza Mahfooz
Christian KönigandChristian König
Dave Airlie
Daniel Vetter
Maíra CanalandMaíra Canal
Oded Gabbay