From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- .../userspace-api/media/v4l/vidioc-qbuf.rst | 197 +++++++++++++++++++++ 1 file changed, 197 insertions(+) create mode 100644 Documentation/userspace-api/media/v4l/vidioc-qbuf.rst (limited to 'Documentation/userspace-api/media/v4l/vidioc-qbuf.rst') diff --git a/Documentation/userspace-api/media/v4l/vidioc-qbuf.rst b/Documentation/userspace-api/media/v4l/vidioc-qbuf.rst new file mode 100644 index 000000000..e4b3d9beb --- /dev/null +++ b/Documentation/userspace-api/media/v4l/vidioc-qbuf.rst @@ -0,0 +1,197 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later +.. c:namespace:: V4L + +.. _VIDIOC_QBUF: + +******************************* +ioctl VIDIOC_QBUF, VIDIOC_DQBUF +******************************* + +Name +==== + +VIDIOC_QBUF - VIDIOC_DQBUF - Exchange a buffer with the driver + +Synopsis +======== + +.. c:macro:: VIDIOC_QBUF + +``int ioctl(int fd, VIDIOC_QBUF, struct v4l2_buffer *argp)`` + +.. c:macro:: VIDIOC_DQBUF + +``int ioctl(int fd, VIDIOC_DQBUF, struct v4l2_buffer *argp)`` + +Arguments +========= + +``fd`` + File descriptor returned by :c:func:`open()`. + +``argp`` + Pointer to struct :c:type:`v4l2_buffer`. + +Description +=========== + +Applications call the ``VIDIOC_QBUF`` ioctl to enqueue an empty +(capturing) or filled (output) buffer in the driver's incoming queue. +The semantics depend on the selected I/O method. + +To enqueue a buffer applications set the ``type`` field of a struct +:c:type:`v4l2_buffer` to the same buffer type as was +previously used with struct :c:type:`v4l2_format` ``type`` +and struct :c:type:`v4l2_requestbuffers` ``type``. +Applications must also set the ``index`` field. Valid index numbers +range from zero to the number of buffers allocated with +:ref:`VIDIOC_REQBUFS` (struct +:c:type:`v4l2_requestbuffers` ``count``) minus +one. The contents of the struct :c:type:`v4l2_buffer` returned +by a :ref:`VIDIOC_QUERYBUF` ioctl will do as well. +When the buffer is intended for output (``type`` is +``V4L2_BUF_TYPE_VIDEO_OUTPUT``, ``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``, +or ``V4L2_BUF_TYPE_VBI_OUTPUT``) applications must also initialize the +``bytesused``, ``field`` and ``timestamp`` fields, see :ref:`buffer` +for details. Applications must also set ``flags`` to 0. The +``reserved2`` and ``reserved`` fields must be set to 0. When using the +:ref:`multi-planar API `, the ``m.planes`` field must +contain a userspace pointer to a filled-in array of struct +:c:type:`v4l2_plane` and the ``length`` field must be set +to the number of elements in that array. + +To enqueue a :ref:`memory mapped ` buffer applications set the +``memory`` field to ``V4L2_MEMORY_MMAP``. When ``VIDIOC_QBUF`` is called +with a pointer to this structure the driver sets the +``V4L2_BUF_FLAG_MAPPED`` and ``V4L2_BUF_FLAG_QUEUED`` flags and clears +the ``V4L2_BUF_FLAG_DONE`` flag in the ``flags`` field, or it returns an +``EINVAL`` error code. + +To enqueue a :ref:`user pointer ` buffer applications set the +``memory`` field to ``V4L2_MEMORY_USERPTR``, the ``m.userptr`` field to +the address of the buffer and ``length`` to its size. When the +multi-planar API is used, ``m.userptr`` and ``length`` members of the +passed array of struct :c:type:`v4l2_plane` have to be used +instead. When ``VIDIOC_QBUF`` is called with a pointer to this structure +the driver sets the ``V4L2_BUF_FLAG_QUEUED`` flag and clears the +``V4L2_BUF_FLAG_MAPPED`` and ``V4L2_BUF_FLAG_DONE`` flags in the +``flags`` field, or it returns an error code. This ioctl locks the +memory pages of the buffer in physical memory, they cannot be swapped +out to disk. Buffers remain locked until dequeued, until the +:ref:`VIDIOC_STREAMOFF ` or +:ref:`VIDIOC_REQBUFS` ioctl is called, or until the +device is closed. + +To enqueue a :ref:`DMABUF ` buffer applications set the +``memory`` field to ``V4L2_MEMORY_DMABUF`` and the ``m.fd`` field to a +file descriptor associated with a DMABUF buffer. When the multi-planar +API is used the ``m.fd`` fields of the passed array of struct +:c:type:`v4l2_plane` have to be used instead. When +``VIDIOC_QBUF`` is called with a pointer to this structure the driver +sets the ``V4L2_BUF_FLAG_QUEUED`` flag and clears the +``V4L2_BUF_FLAG_MAPPED`` and ``V4L2_BUF_FLAG_DONE`` flags in the +``flags`` field, or it returns an error code. This ioctl locks the +buffer. Locking a buffer means passing it to a driver for a hardware +access (usually DMA). If an application accesses (reads/writes) a locked +buffer then the result is undefined. Buffers remain locked until +dequeued, until the :ref:`VIDIOC_STREAMOFF ` or +:ref:`VIDIOC_REQBUFS` ioctl is called, or until the +device is closed. + +The ``request_fd`` field can be used with the ``VIDIOC_QBUF`` ioctl to specify +the file descriptor of a :ref:`request `, if requests are +in use. Setting it means that the buffer will not be passed to the driver +until the request itself is queued. Also, the driver will apply any +settings associated with the request for this buffer. This field will +be ignored unless the ``V4L2_BUF_FLAG_REQUEST_FD`` flag is set. +If the device does not support requests, then ``EBADR`` will be returned. +If requests are supported but an invalid request file descriptor is given, +then ``EINVAL`` will be returned. + +.. caution:: + It is not allowed to mix queuing requests with queuing buffers directly. + ``EBUSY`` will be returned if the first buffer was queued directly and + then the application tries to queue a request, or vice versa. After + closing the file descriptor, calling + :ref:`VIDIOC_STREAMOFF ` or calling :ref:`VIDIOC_REQBUFS` + the check for this will be reset. + + For :ref:`memory-to-memory devices ` you can specify the + ``request_fd`` only for output buffers, not for capture buffers. Attempting + to specify this for a capture buffer will result in an ``EBADR`` error. + +Applications call the ``VIDIOC_DQBUF`` ioctl to dequeue a filled +(capturing) or displayed (output) buffer from the driver's outgoing +queue. They just set the ``type``, ``memory`` and ``reserved`` fields of +a struct :c:type:`v4l2_buffer` as above, when +``VIDIOC_DQBUF`` is called with a pointer to this structure the driver +fills all remaining fields or returns an error code. The driver may also +set ``V4L2_BUF_FLAG_ERROR`` in the ``flags`` field. It indicates a +non-critical (recoverable) streaming error. In such case the application +may continue as normal, but should be aware that data in the dequeued +buffer might be corrupted. When using the multi-planar API, the planes +array must be passed in as well. + +If the application sets the ``memory`` field to ``V4L2_MEMORY_DMABUF`` to +dequeue a :ref:`DMABUF ` buffer, the driver fills the ``m.fd`` field +with a file descriptor numerically the same as the one given to ``VIDIOC_QBUF`` +when the buffer was enqueued. No new file descriptor is created at dequeue time +and the value is only for the application convenience. When the multi-planar +API is used the ``m.fd`` fields of the passed array of struct +:c:type:`v4l2_plane` are filled instead. + +By default ``VIDIOC_DQBUF`` blocks when no buffer is in the outgoing +queue. When the ``O_NONBLOCK`` flag was given to the +:c:func:`open()` function, ``VIDIOC_DQBUF`` returns +immediately with an ``EAGAIN`` error code when no buffer is available. + +The struct :c:type:`v4l2_buffer` structure is specified in +:ref:`buffer`. + +Return Value +============ + +On success 0 is returned, on error -1 and the ``errno`` variable is set +appropriately. The generic error codes are described at the +:ref:`Generic Error Codes ` chapter. + +EAGAIN + Non-blocking I/O has been selected using ``O_NONBLOCK`` and no + buffer was in the outgoing queue. + +EINVAL + The buffer ``type`` is not supported, or the ``index`` is out of + bounds, or no buffers have been allocated yet, or the ``userptr`` or + ``length`` are invalid, or the ``V4L2_BUF_FLAG_REQUEST_FD`` flag was + set but the given ``request_fd`` was invalid, or ``m.fd`` was + an invalid DMABUF file descriptor. + +EIO + ``VIDIOC_DQBUF`` failed due to an internal error. Can also indicate + temporary problems like signal loss. + + .. note:: + + The driver might dequeue an (empty) buffer despite returning + an error, or even stop capturing. Reusing such buffer may be unsafe + though and its details (e.g. ``index``) may not be returned either. + It is recommended that drivers indicate recoverable errors by setting + the ``V4L2_BUF_FLAG_ERROR`` and returning 0 instead. In that case the + application should be able to safely reuse the buffer and continue + streaming. + +EPIPE + ``VIDIOC_DQBUF`` returns this on an empty capture queue for mem2mem + codecs if a buffer with the ``V4L2_BUF_FLAG_LAST`` was already + dequeued and no new buffers are expected to become available. + +EBADR + The ``V4L2_BUF_FLAG_REQUEST_FD`` flag was set but the device does not + support requests for the given buffer type, or + the ``V4L2_BUF_FLAG_REQUEST_FD`` flag was not set but the device requires + that the buffer is part of a request. + +EBUSY + The first buffer was queued via a request, but the application now tries + to queue it directly, or vice versa (it is not permitted to mix the two + APIs). -- cgit v1.2.3