According to the eDP specification (VESA Embedded DisplayPort Standard
v1.4b, Section 3.3.10.2), if the value of DP_EDP_PWMGEN_BIT_COUNT is
less than DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, the sink is required to use
the MIN value as the effective PWM bit count.
This commit updates the logic to clamp the reported
DP_EDP_PWMGEN_BIT_COUNT to the range defined by _CAP_MIN and _CAP_MAX.
As part of this change, the behavior is modified such that reading both
_CAP_MIN and _CAP_MAX registers is now required to succeed, otherwise
bl->max value could end up being not set although
drm_edp_backlight_probe_max() returned success.
This ensures correct handling of eDP panels that report a zero PWM
bit count but still provide valid non-zero MIN and MAX capability
values. Without this clamping, brightness values may be interpreted
incorrectly, leading to a dim or non-functional backlight.
For example, the Samsung ATNA40YK20 OLED panel used in the Lenovo
ThinkPad T14s Gen6 (Snapdragon) reports a PWM bit count of 0, but
supports AUX backlight control and declares a valid 11-bit range.
Clamping ensures brightness scaling works as intended on such panels.
Co-developed-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Christopher Obbard <christopher.obbard@linaro.org>
Tested-by: Christopher Obbard <christopher.obbard@linaro.org>
Reviewed-by: Christopher Obbard <christopher.obbard@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20250814-topic-x1e80100-t14s-oled-dp-brightness-v7-1-b3d7b4dfe8c5@linaro.org
Replace vkms' vblank timer with the DRM implementation. The DRM
code is identical in concept, but differs in implementation.
Vblank timers are covered in vblank helpers and initializer macros,
so remove the corresponding hrtimer in struct vkms_output. The
vblank timer calls vkms' custom timeout code via handle_vblank_timeout
in struct drm_crtc_helper_funcs.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Louis Chauvet <louis.chauvet@bootlin.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://lore.kernel.org/r/20250916083816.30275-4-tzimmermann@suse.de
Implement atomic_flush, atomic_enable and atomic_disable of struct
drm_crtc_helper_funcs for vblank handling. Driver with no further
requirements can use these functions instead of adding their own.
Also simplifies the use of vblank timers.
The code has been adopted from vkms, which added the funtionality
in commit 3a0709928b ("drm/vkms: Add vblank events simulated by
hrtimers").
v3:
- mention vkms (Javier)
v2:
- fix docs
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20250916083816.30275-3-tzimmermann@suse.de
The vblank timer simulates a vblank interrupt for hardware without
support. Rate-limits the display update frequency.
DRM drivers for hardware without vblank support apply display updates
ASAP. A vblank event informs DRM clients of the completed update.
Userspace compositors immediately schedule the next update, which
creates significant load on virtualization outputs. Display updates
are usually fast on virtualization outputs, as their framebuffers are
in regular system memory and there's no hardware vblank interrupt to
throttle the update rate.
The vblank timer is a HR timer that signals the vblank in software.
It limits the update frequency of a DRM driver similar to a hardware
vblank interrupt. The timer is not synchronized to the actual vblank
interval of the display.
The code has been adopted from vkms, which added the funtionality
in commit 3a0709928b ("drm/vkms: Add vblank events simulated by
hrtimers").
The new implementation is part of the existing vblank support,
which sets up the timer automatically. Drivers only have to start
and cancel the vblank timer as part of enabling and disabling the
CRTC. The new vblank helper library provides callbacks for struct
drm_crtc_funcs.
The standard way for handling vblank is to call drm_crtc_handle_vblank().
Drivers that require additional processing, such as vkms, can init
handle_vblank_timeout in struct drm_crtc_helper_funcs to refer to
their timeout handler.
There's a possible deadlock between drm_crtc_handle_vblank() and
hrtimer_cancel(). [1] The implementation avoids to call hrtimer_cancel()
directly and instead signals to the timer function to not restart
itself.
v4:
- fix possible race condition between timeout and atomic commit (Michael)
v3:
- avoid deadlock when cancelling timer (Ville, Lyude)
v2:
- implement vblank timer entirely in vblank helpers
- downgrade overrun warning to debug
- fix docs
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Louis Chauvet <louis.chauvet@bootlin.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/all/20250510094757.4174662-1-zengheng4@huawei.com/ # [1]
Link: https://lore.kernel.org/r/20250916083816.30275-2-tzimmermann@suse.de
Pull rust updates from Miguel Ojeda:
"Toolchain and infrastructure:
- Derive 'Zeroable' for all structs and unions generated by 'bindgen'
where possible and corresponding cleanups. To do so, add the
'pin-init' crate as a dependency to 'bindings' and 'uapi'.
It also includes its first use in the 'cpufreq' module, with more
to come in the next cycle.
- Add warning to the 'rustdoc' target to detect broken 'srctree/'
links and fix existing cases.
- Remove support for unused (since v6.16) host '#[test]'s,
simplifying the 'rusttest' target. Tests should generally run
within KUnit.
'kernel' crate:
- Add 'ptr' module with a new 'Alignment' type, which is always a
power of two and is used to validate that a given value is a valid
alignment and to perform masking and alignment operations:
// Checked at build time.
assert_eq!(Alignment:🆕:<16>().as_usize(), 16);
// Checked at runtime.
assert_eq!(Alignment::new_checked(15), None);
assert_eq!(Alignment::of::<u8>().log2(), 0);
assert_eq!(0x25u8.align_down(Alignment:🆕:<0x10>()), 0x20);
assert_eq!(0x5u8.align_up(Alignment:🆕:<0x10>()), Some(0x10));
assert_eq!(u8::MAX.align_up(Alignment:🆕:<0x10>()), None);
It also includes its first use in Nova.
- Add 'core::mem::{align,size}_of{,_val}' to the prelude, matching
Rust 1.80.0.
- Keep going with the steps on our migration to the standard library
'core::ffi::CStr' type (use 'kernel::{fmt, prelude::fmt!}' and use
upstream method names).
- 'error' module: improve 'Error::from_errno' and 'to_result'
documentation, including examples/tests.
- 'sync' module: extend 'aref' submodule documentation now that it
exists, and more updates to complete the ongoing move of 'ARef' and
'AlwaysRefCounted' to 'sync::aref'.
- 'list' module: add an example/test for 'ListLinksSelfPtr' usage.
- 'alloc' module:
- Implement 'Box::pin_slice()', which constructs a pinned slice of
elements.
- Provide information about the minimum alignment guarantees of
'Kmalloc', 'Vmalloc' and 'KVmalloc'.
- Take minimum alignment guarantees of allocators for
'ForeignOwnable' into account.
- Remove the 'allocator_test' (including 'Cmalloc').
- Add doctest for 'Vec::as_slice()'.
- Constify various methods.
- 'time' module:
- Add methods on 'HrTimer' that can only be called with exclusive
access to an unarmed timer, or from timer callback context.
- Add arithmetic operations to 'Instant' and 'Delta'.
- Add a few convenience and access methods to 'HrTimer' and
'Instant'.
'macros' crate:
- Reduce collections in 'quote!' macro.
And a few other cleanups and improvements"
* tag 'rust-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (58 commits)
gpu: nova-core: use Alignment for alignment-related operations
rust: add `Alignment` type
rust: macros: reduce collections in `quote!` macro
rust: acpi: use `core::ffi::CStr` method names
rust: of: use `core::ffi::CStr` method names
rust: net: use `core::ffi::CStr` method names
rust: miscdevice: use `core::ffi::CStr` method names
rust: kunit: use `core::ffi::CStr` method names
rust: firmware: use `core::ffi::CStr` method names
rust: drm: use `core::ffi::CStr` method names
rust: cpufreq: use `core::ffi::CStr` method names
rust: configfs: use `core::ffi::CStr` method names
rust: auxiliary: use `core::ffi::CStr` method names
drm/panic: use `core::ffi::CStr` method names
rust: device: use `kernel::{fmt,prelude::fmt!}`
rust: sync: use `kernel::{fmt,prelude::fmt!}`
rust: seq_file: use `kernel::{fmt,prelude::fmt!}`
rust: kunit: use `kernel::{fmt,prelude::fmt!}`
rust: file: use `kernel::{fmt,prelude::fmt!}`
rust: device: use `kernel::{fmt,prelude::fmt!}`
...
At present VMBus driver is hinged off of CONFIG_HYPERV which entails
lot of builtin code and encompasses too much. It's not always clear
what depends on builtin hv code and what depends on VMBus. Setting
CONFIG_HYPERV as a module and fudging the Makefile to switch to builtin
adds even more confusion. VMBus is an independent module and should have
its own config option. Also, there are scenarios like baremetal dom0/root
where support is built in with CONFIG_HYPERV but without VMBus. Lastly,
there are more features coming down that use CONFIG_HYPERV and add more
dependencies on it.
So, create a fine grained HYPERV_VMBUS option and update Kconfigs for
dependency on VMBus.
Signed-off-by: Mukesh Rathor <mrathor@linux.microsoft.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # drivers/pci
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Don't mix dma fence lock with the active_job lock. Use fence_lock to
protect the dma fence used by drm scheduler when signalling a job
completion and queue_lock to protect concurrent access to active bin job
in OOM and stats collection for a given file priv. The issue was
uncovered when PREEMPT_RT on with a system freeze when opening multiple
Chromium tabs on Raspberry Pi 5.
Link: https://github.com/raspberrypi/linux/issues/7035
Fixes: fa6a20c874 ("drm/v3d: Address race-condition between per-fd GPU stats and fd release")
Signed-off-by: Melissa Wen <mwen@igalia.com>
Acked-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
Signed-off-by: Melissa Wen <melissa.srw@gmail.com>
Link: https://lore.kernel.org/r/20250916172022.2779837-1-mwen@igalia.com
The tidss_crtc_reset() function will (rightfully) destroy any
pre-existing state.
However, the tidss CRTC driver has its own CRTC state structure that
subclasses drm_crtc_state, and yet will destroy the previous state
by calling __drm_atomic_helper_crtc_destroy_state() and kfree() on its
drm_crtc_state pointer.
It works only because the drm_crtc_state is the first field in the
structure, and thus its offset is 0. It's incredibly fragile however, so
let's call our destroy implementation in such a case to deal with it
properly.
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20250902-drm-state-readout-v1-22-14ad5315da3f@kernel.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250902-drm-state-readout-v1-22-14ad5315da3f@kernel.org
The error irq handling needs to mask page table errors on gen 2/3 with
FBC. See commit e7e12f6ec8 ("drm/i915: Mask page table errors on
gen2/3 with FBC") for details.
We want to avoid using display feature checks in i915 core code. Since
FBC can't be fused off on gen 2/3, just list the platforms that support
FBC. Add a macro purely for making the code self-documenting.
With this, we can drop the intel_display_core.h include, and make struct
intel_display opaque inside i915_irq.c.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/20250929133418.2033006-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Due to initial design of the Xe debugfs, the GGTT and LMEM files
were defined on the primary GT, instead of being per-tile.
While PF provisioning code is now still maintaining GGTT and LMEM
also on the per primary-GT level, this will be refactored soon,
but we can fix debugfs layout now, as part of the new SR-IOV tree.
For backward compatibility we will provide some symlinks that can
be removed once our tools will be fully converted.
As we are making all those changes in the user facing interface,
take this as apportunity to also start replacing the "LMEM" term,
used by the SR-IOV code, with the "VRAM" term, used by Xe driver.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20250928140029.198847-7-michal.wajdeczko@intel.com
Currently we expose debugfs files related to SR-IOV functions
together with other native files, but that approach will not
scale well as we plan to add more attributes and also expose
some of them on the per-tile basis.
Start building separate tree for SR-IOV specific debugfs files
where we can replicate similar files per every SR-IOV function:
/sys/kernel/debug/dri/BDF/
├── sriov
│ ├── pf
│ │ ├── tile0
│ │ │ ├── gt0
│ │ │ ├── gt1
│ │ │ :
│ │ ├── tile1
│ │ :
│ ├── vf1
│ │ ├── tile0
│ │ │ ├── gt0
│ │ │ ├── gt1
│ │ │ :
│ │ :
│ ├── vf2
│ ├── ...
We will populate this new tree in upcoming patches.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://lore.kernel.org/r/20250928140029.198847-3-michal.wajdeczko@intel.com
