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author | 2023-02-21 18:24:12 -0800 | |
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committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/userspace-api/media/v4l/dev-osd.rst | |
download | linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip |
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski:
"Core:
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used to
describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on
boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols:
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF:
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
better support decap on GRE tunnel devices not operating in collect
metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk and
bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols by
livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter:
- Remove the CLUSTERIP target. It has been marked as obsolete for
years, and we still have WARN splats wrt races of the out-of-band
/proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to the
existing 'delete' commands, but do not return an error if the
referenced object (set, chain, rule...) did not exist.
Driver API:
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into
multiple files, drop some of the unnecessarily granular locks and
factor out common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless
Extensions for Wi-Fi 7 devices at all. Everyone should switch to
using nl80211 interface instead.
- Improve the CAN bit timing configuration. Use extack to return
error messages directly to user space, update the SJW handling,
including the definition of a new default value that will benefit
CAN-FD controllers, by increasing their oscillator tolerance.
New hardware / drivers:
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers:
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- support XDP_REDIRECT for XDP non-linear buffers
- improve reconfig, avoid link flap and waiting for idle
- support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q,
8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation"
* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
page_pool: add a comment explaining the fragment counter usage
net: ethtool: fix __ethtool_dev_mm_supported() implementation
ethtool: pse-pd: Fix double word in comments
xsk: add linux/vmalloc.h to xsk.c
sefltests: netdevsim: wait for devlink instance after netns removal
selftest: fib_tests: Always cleanup before exit
net/mlx5e: Align IPsec ASO result memory to be as required by hardware
net/mlx5e: TC, Set CT miss to the specific ct action instance
net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
net/mlx5: Refactor tc miss handling to a single function
net/mlx5: Kconfig: Make tc offload depend on tc skb extension
net/sched: flower: Support hardware miss to tc action
net/sched: flower: Move filter handle initialization earlier
net/sched: cls_api: Support hardware miss to tc action
net/sched: Rename user cookie and act cookie
sfc: fix builds without CONFIG_RTC_LIB
sfc: clean up some inconsistent indentings
net/mlx4_en: Introduce flexible array to silence overflow warning
net: lan966x: Fix possible deadlock inside PTP
net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
...
Diffstat (limited to '')
-rw-r--r-- | Documentation/userspace-api/media/v4l/dev-osd.rst | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/v4l/dev-osd.rst b/Documentation/userspace-api/media/v4l/dev-osd.rst new file mode 100644 index 000000000..8e4be9129 --- /dev/null +++ b/Documentation/userspace-api/media/v4l/dev-osd.rst @@ -0,0 +1,150 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later + +.. _osd: + +****************************** +Video Output Overlay Interface +****************************** + +**Also known as On-Screen Display (OSD)** + +Some video output devices can overlay a framebuffer image onto the +outgoing video signal. Applications can set up such an overlay using +this interface, which borrows structures and ioctls of the +:ref:`Video Overlay <overlay>` interface. + +The OSD function is accessible through the same character special file +as the :ref:`Video Output <capture>` function. + +.. note:: + + The default function of such a ``/dev/video`` device is video + capturing or output. The OSD function is only available after calling + the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl. + + +Querying Capabilities +===================== + +Devices supporting the *Video Output Overlay* interface set the +``V4L2_CAP_VIDEO_OUTPUT_OVERLAY`` flag in the ``capabilities`` field of +struct :c:type:`v4l2_capability` returned by the +:ref:`VIDIOC_QUERYCAP` ioctl. + + +Framebuffer +=========== + +Contrary to the *Video Overlay* interface the framebuffer is normally +implemented on the TV card and not the graphics card. On Linux it is +accessible as a framebuffer device (``/dev/fbN``). Given a V4L2 device, +applications can find the corresponding framebuffer device by calling +the :ref:`VIDIOC_G_FBUF <VIDIOC_G_FBUF>` ioctl. It returns, amongst +other information, the physical address of the framebuffer in the +``base`` field of struct :c:type:`v4l2_framebuffer`. +The framebuffer device ioctl ``FBIOGET_FSCREENINFO`` returns the same +address in the ``smem_start`` field of struct +:c:type:`fb_fix_screeninfo`. The ``FBIOGET_FSCREENINFO`` +ioctl and struct :c:type:`fb_fix_screeninfo` are defined in +the ``linux/fb.h`` header file. + +The width and height of the framebuffer depends on the current video +standard. A V4L2 driver may reject attempts to change the video standard +(or any other ioctl which would imply a framebuffer size change) with an +``EBUSY`` error code until all applications closed the framebuffer device. + +Example: Finding a framebuffer device for OSD +--------------------------------------------- + +.. code-block:: c + + #include <linux/fb.h> + + struct v4l2_framebuffer fbuf; + unsigned int i; + int fb_fd; + + if (-1 == ioctl(fd, VIDIOC_G_FBUF, &fbuf)) { + perror("VIDIOC_G_FBUF"); + exit(EXIT_FAILURE); + } + + for (i = 0; i < 30; i++) { + char dev_name[16]; + struct fb_fix_screeninfo si; + + snprintf(dev_name, sizeof(dev_name), "/dev/fb%u", i); + + fb_fd = open(dev_name, O_RDWR); + if (-1 == fb_fd) { + switch (errno) { + case ENOENT: /* no such file */ + case ENXIO: /* no driver */ + continue; + + default: + perror("open"); + exit(EXIT_FAILURE); + } + } + + if (0 == ioctl(fb_fd, FBIOGET_FSCREENINFO, &si)) { + if (si.smem_start == (unsigned long)fbuf.base) + break; + } else { + /* Apparently not a framebuffer device. */ + } + + close(fb_fd); + fb_fd = -1; + } + + /* fb_fd is the file descriptor of the framebuffer device + for the video output overlay, or -1 if no device was found. */ + + +Overlay Window and Scaling +========================== + +The overlay is controlled by source and target rectangles. The source +rectangle selects a subsection of the framebuffer image to be overlaid, +the target rectangle an area in the outgoing video signal where the +image will appear. Drivers may or may not support scaling, and arbitrary +sizes and positions of these rectangles. Further drivers may support any +(or none) of the clipping/blending methods defined for the +:ref:`Video Overlay <overlay>` interface. + +A struct :c:type:`v4l2_window` defines the size of the +source rectangle, its position in the framebuffer and the +clipping/blending method to be used for the overlay. To get the current +parameters applications set the ``type`` field of a struct +:c:type:`v4l2_format` to +``V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY`` and call the +:ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` ioctl. The driver fills the +struct :c:type:`v4l2_window` substructure named ``win``. It is not +possible to retrieve a previously programmed clipping list or bitmap. + +To program the source rectangle applications set the ``type`` field of a +struct :c:type:`v4l2_format` to +``V4L2_BUF_TYPE_VIDEO_OUTPUT_OVERLAY``, initialize the ``win`` +substructure and call the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl. +The driver adjusts the parameters against hardware limits and returns +the actual parameters as :ref:`VIDIOC_G_FMT <VIDIOC_G_FMT>` does. Like :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>`, +the :ref:`VIDIOC_TRY_FMT <VIDIOC_G_FMT>` ioctl can be used to learn +about driver capabilities without actually changing driver state. Unlike +:ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` this also works after the overlay has been enabled. + +A struct :c:type:`v4l2_crop` defines the size and position +of the target rectangle. The scaling factor of the overlay is implied by +the width and height given in struct :c:type:`v4l2_window` +and struct :c:type:`v4l2_crop`. The cropping API applies to +*Video Output* and *Video Output Overlay* devices in the same way as to +*Video Capture* and *Video Overlay* devices, merely reversing the +direction of the data flow. For more information see :ref:`crop`. + + +Enabling Overlay +================ + +There is no V4L2 ioctl to enable or disable the overlay, however the +framebuffer interface of the driver may support the ``FBIOBLANK`` ioctl. |