Searched full:to (Results 1 – 25 of 4513) sorted by relevance
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| /Documentation/devicetree/bindings/power/ |
| D | rockchip-io-domain.yaml | 13 IO domain voltages on some Rockchip SoCs are variable but need to be
18 If the regulator hooked up to a pin like SDMMC0_VDD is 3.3V then
19 bit 7 of GRF_IO_VSEL needs to be 0. If the regulator hooked up to
20 that same pin is 1.8V then bit 7 of GRF_IO_VSEL needs to be 1.
24 hooked up to the pins.
27 any logic for deciding what voltage we should set regulators to
42 to report their voltage. The IO Voltage Domain for any non-specified
97 description: The supply connected to VCCIO1.
99 description: The supply connected to VCCIO2.
101 description: The supply connected to VCCIO3.
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| /Documentation/driver-api/pm/ |
| D | cpuidle.rst | 16 Every time one of the logical CPUs in the system (the entities that appear to
19 there are no tasks to run on it except for the special "idle" task associated
20 with it, there is an opportunity to save energy for the processor that it
21 belongs to. That can be done by making the idle logical CPU stop fetching
26 situation in principle, so it may be necessary to find the most suitable one
27 (from the kernel perspective) and ask the processor to use (or "enter") that
35 units: *governors* responsible for selecting idle states to ask the processor
36 to enter, *drivers* that pass the governors' decisions on to the hardware and
44 one of the logical CPUs in the system turns out to be idle. Its role is to
45 select an idle state to ask the processor to enter in order to save some energy.
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| /Documentation/filesystems/xfs/ |
| D | xfs-delayed-logging-design.rst | 18 reservations bounds. At this point we need to explain how relogging works. With
26 XFS uses Write Ahead Logging for ensuring changes to the filesystem metadata
29 physical logging mechanisms to provide the necessary recovery guarantees the
33 details logged are made up of the changes to in-core structures rather than
40 The reason for these differences is to keep the amount of log space and CPU time
41 required to process objects being modified as small as possible and hence the
46 The method used to log an item or chain modifications together isn't
47 particularly important in the scope of this document. It suffices to know that
51 followed to guarantee forwards progress and prevent deadlocks.
63 The type and size of reservation must be matched to the modification taking
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| /Documentation/bpf/ |
| D | prog_cgroup_sysctl.rst | 10 The hook has to be attached to a cgroup and will be called every time a
11 process inside that cgroup tries to read from or write to sysctl knob in proc.
16 ``BPF_CGROUP_SYSCTL`` attach type has to be used to attach
17 ``BPF_PROG_TYPE_CGROUP_SYSCTL`` program to a cgroup.
22 ``BPF_PROG_TYPE_CGROUP_SYSCTL`` provides access to the following context from
34 or written. This field is read-write. Writing to the field sets the starting
36 will be writing to. Writing zero to the field can be used e.g. to override
39 value to the field can be used to access part of sysctl value starting from
41 0``, e.g. writes to numeric sysctl entries must always be at file position
52 * ``0`` means "reject access to sysctl";
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| /Documentation/filesystems/ |
| D | netfs_library.rst | 23 The network filesystem helper library is a set of functions designed to aid a
25 just includes turning various VM buffered read operations into requests to read
36 The network filesystem helper library needs a place to store a bit of state for
37 its use on each netfs inode it is helping to manage. To this end, a context
46 A network filesystem that wants to use netfs lib must place one of these in its
48 a way similar to the following::
55 This allows netfslib to find its state by using ``container_of()`` from the
56 inode pointer, thereby allowing the netfslib helper functions to be pointed to
67 The set of operations provided by the network filesystem to netfslib.
78 To help deal with the per-inode context, a number helper functions are
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| D | journalling.rst | 10 The journalling layer is easy to use. You need to first of all create a
11 journal_t data structure. There are two calls to do this dependent on
12 how you decide to allocate the physical media on which the journal
17 finished make sure you call jbd2_journal_destroy() on it to free up
20 Once you have got your journal_t object you need to 'mount' or load the
23 When loading the journal you must call jbd2_journal_load() to process
25 does not need to be processed (or even need not have valid contents), it
26 may call jbd2_journal_wipe() to clear the journal contents before
38 You still need to actually journal your filesystem changes, this is done
39 by wrapping them into transactions. Additionally you also need to wrap
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| /Documentation/ABI/testing/ |
| D | configfs-most | 4 Description: Interface is used to configure and connect device channels
5 to component drivers.
7 Attributes are visible only when configfs is mounted. To mount
49 name of the device the link is to be attached to
52 name of the channel the link is to be attached to
58 write '1' to this attribute to trigger the
61 a physical device is being attached to the bus.
64 write '1' to this attribute to destroy an
104 name of the device the link is to be attached to
107 name of the channel the link is to be attached to
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| /Documentation/networking/ |
| D | ppp_generic.rst | 16 * the interface to the networking code
19 * the interface to pppd, via a /dev/ppp character device
27 mechanism for transporting PPP frames from one machine to another. A
30 to be able to send PPP frames, receive PPP frames, and optionally
35 This architecture makes it possible to implement PPP multilink in a
36 natural and straightforward way, by allowing more than one channel to
37 be linked to each ppp network interface unit. The generic layer is
46 functions used to communicate between the generic PPP layer and PPP
49 Each channel has to provide two functions to the generic PPP layer,
52 * start_xmit() is called by the generic layer when it has a frame to
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| D | operstates.rst | 13 <dev> up or down" and reflects whether the administrator wants to use
17 - ethernet requires to be plugged into the switch and, depending on
19 to be performed before user data can be transferred. Operational state
20 shows the ability of an interface to transmit this user data.
22 Thanks to 802.1X, userspace must be granted the possibility to
23 influence operational state. To accommodate this, operational state is
33 operation RTM_GETLINK. It is also possible to subscribe to RTNLGRP_LINK
34 to be notified of updates while the interface is admin up. This is
45 flag to determine whether they should use the interface.
68 Interface is unable to transfer data on L1, f.e. ethernet is not
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| /Documentation/process/ |
| D | 7.AdvancedTopics.rst | 7 works. There is still more to learn, however! This section will cover a
8 number of topics which can be helpful for developers wanting to become a
16 application. While BitKeeper was controversial, the approach to software
19 project. In current times, there are several free alternatives to
26 still being civilized by its developers. This document will not attempt to
27 teach the reader how to use git; that would be sufficient material for a
30 wish to come up to speed with git will find more information at:
38 The first order of business is to read the above sites and get a solid
39 understanding of how git works before trying to use it to make patches
40 available to others. A git-using developer should be able to obtain a copy
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| D | 6.Followthrough.rst | 9 developers can make is to conclude that their work is now done. In truth,
11 with, possibly, quite a bit of work yet to be done.
16 code. You, as the author of that code, will be expected to work with the
17 kernel community to ensure that your code is up to the kernel's quality
18 standards. A failure to participate in this process is quite likely to
32 value and why you went to the trouble of writing it. But that value
34 like to maintain a kernel with this code in it five or ten years later?
35 Many of the changes you may be asked to make - from coding style tweaks
36 to substantial rewrites - come from the understanding that Linux will
44 impulse to respond in kind. Code review is about the code, not about
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| D | 3.Early-stage.rst | 7 to jump right in and start coding. As with any significant project,
17 clear description of the problem to be solved. In some cases, this step is
19 example. In others, though, it is tempting to confuse the real problem
20 with the proposed solution, and that can lead to difficulties.
23 sought a way to run applications without dropouts or other artifacts caused
25 kernel module intended to hook into the Linux Security Module (LSM)
26 framework; this module could be configured to give specific applications
27 access to the realtime scheduler. This module was implemented and sent to
30 To the audio developers, this security module was sufficient to solve their
31 immediate problem. To the wider kernel community, though, it was seen as a
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| /Documentation/accel/qaic/ |
| D | qaic.rst | 17 mechanism, it is still possible for an IRQ storm to occur. A storm can happen
20 it, then the device will frequently transition the response FIFO from empty to
21 non-empty and generate MSIs at a rate equivalent to the speed of the
22 workload's ability to process inputs. The lprnet (license plate reader network)
23 workload is known to trigger this condition, and can generate in excess of 100k
25 for long, and will crash due to some form of watchdog due to the overhead of
28 To mitigate this issue, the QAIC driver implements specific IRQ handling. When
32 sleep for a time to see if the workload will generate more activity. The IRQ
37 generates 100k IRQs per second (per /proc/interrupts) is reduced to roughly 64
39 workload throughput performance (within run to run noise variation).
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| /Documentation/admin-guide/pm/ |
| D | sleep-states.rst | 22 the Linux kernel can support up to four system sleep states, including
23 hibernation and up to three variants of system suspend. The sleep states that
28 Suspend-to-Idle
32 referred to as S2I or S2Idle). It allows more energy to be saved relative to
39 any devices that can cause interrupts to be generated in the working state can
43 or :ref:`suspend-to-RAM <s2ram>`, or it can be used in addition to any of the
44 deeper system suspend variants to provide reduced resume latency. It is always
53 providing a relatively straightforward transition back to the working state. No
55 go back to where it left off easily enough.
57 In addition to freezing user space, suspending the timekeeping and putting all
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| D | cpufreq.rst | 19 different clock frequency and voltage configurations, often referred to as
28 In some situations it is desirable or even necessary to run the program as fast
29 as possible and then there is no reason to use any P-states different from the
31 available). In some other cases, however, it may not be necessary to execute
34 It also may not be physically possible to maintain maximum CPU capacity for too
35 long for thermal or power supply capacity reasons or similar. To cover those
36 cases, there are hardware interfaces allowing CPUs to be switched between
37 different frequency/voltage configurations or (in the ACPI terminology) to be
40 Typically, they are used along with algorithms to estimate the required CPU
41 capacity, so as to decide which P-states to put the CPUs into. Of course, since
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| D | cpuidle.rst | 19 Modern processors are generally able to enter states in which the execution of
20 a program is suspended and instructions belonging to it are not fetched from
24 generally allows power drawn by the processor to be reduced and, in consequence,
25 it is an opportunity to save energy.
36 not be separate physical entities and may just be interfaces appearing to
38 entity which appears to be fetching instructions that belong to one sequence
43 program) at a time, it is a CPU. In that case, if the hardware is asked to
44 enter an idle state, that applies to the processor as a whole.
46 Second, if the processor is multi-core, each core in it is able to follow at
51 time. The entire cores are CPUs in that case and if the hardware is asked to
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| /Documentation/firmware-guide/acpi/ |
| D | osi.rst | 8 to find out what the operating system supports. Eg. If BIOS
10 can evaluate that method, look to see if it supports 'XYZ'
11 and answer YES or NO to the BIOS.
19 How to use _OSI
23 to be compatible with Linux, and those that were never tested with Linux,
24 but where Linux was installed to replace the original OS (Windows or OSX).
26 The larger group is the systems tested to run only Windows. Not only that,
27 but many were tested to run with just one specific version of Windows.
28 So even though the BIOS may use _OSI to query what version of Windows is running,
31 exposes Linux to an entire category of BIOS bugs.
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| /Documentation/admin-guide/device-mapper/ |
| D | vdo-design.rst | 9 can be backed by up to 256TB of storage, and can present a logical size of
10 up to 4PB. This target was originally developed at Permabit Technology
18 deduplication rates of 254:1, i.e. up to 254 copies of a given 4K block can
26 problem. The first is to recognize duplicate data. The second is to avoid
28 parts: a deduplication index (called UDS) that is used to discover
30 maps from logical block addresses to the actual storage location of the
36 Due to the complexity of data optimization, the number of metadata
37 structures involved in a single write operation to a vdo target is larger
39 block sizes in order to achieve good deduplication rates, acceptable
41 design attempts to be lock-free.
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| /Documentation/scsi/ |
| D | ChangeLog.lpfc | 5 Changes from 20050323 to 20050413
7 * Changed version number to 8.0.28
10 * Removed pci dma sync calls to coherent/consistent pci memory.
13 * Removed sysfs attributes that are used to dump the various
17 to luns on nodes in NPR or other relevant states (PLOGI,
23 * Removed extraneous calls to lpfc_sli_next_iotag which should
29 if we timed out waiting for command to complete after abort was
31 * Zero-out response sense length in lpfc_scsi_prep_cmnd to prevent
45 driver has already returned the command to the midlayer.
47 Changes from 20050308 to 20050323
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| /Documentation/driver-api/ |
| D | device_link.rst | 13 Sometimes there is a need to represent device dependencies beyond the
18 dependencies, i.e. that one device must be bound to a driver before
22 another one both with regards to driver presence *and* with regards to
31 supplier is bound to a driver, and they're unbound before the supplier
41 is instructed to runtime resume the supplier and keep it active
51 It is legal to add them later, but care must be taken that the system
54 such a transition needs to be prevented with :c:func:`lock_system_sleep()`,
55 or the device link needs to be added from a function which is guaranteed
56 not to run in parallel to a suspend/resume transition, such as from a
61 ``->probe`` callback while the supplier hasn't started to probe yet: Had the
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| /Documentation/userspace-api/ |
| D | iommufd.rst | 13 IOMMUFD is the user API to control the IOMMU subsystem as it relates to managing
14 IO page tables from userspace using file descriptors. It intends to be general
15 and consumable by any driver that wants to expose DMA to userspace. These
16 drivers are eventually expected to deprecate any internal IOMMU logic
20 I/O page tables for all IOMMUs, with room in the design to add non-generic
21 features to cater to specific hardware functionality.
23 In this context the capital letter (IOMMUFD) refers to the subsystem while the
24 small letter (iommufd) refers to the file descriptors created via /dev/iommu for
33 Following IOMMUFD objects are exposed to userspace:
39 container it copies an IOVA map to a list of iommu_domains held within it.
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| /Documentation/trace/ |
| D | user_events.rst | 9 User based trace events allow user processes to create events and trace data
11 To enable this feature, build your kernel with CONFIG_USER_EVENTS=y.
17 Programs can also use /sys/kernel/tracing/dynamic_events to register and
18 delete user based events via the u: prefix. The format of the command to
20 requires CAP_PERFMON due to the event persisting, otherwise -EPERM is returned.
22 Typically programs will register a set of events that they wish to expose to
24 process tells the kernel which address and bit to reflect if any tool has
37 Registering within a user process is done via ioctl() out to the
38 /sys/kernel/tracing/user_events_data file. The command to issue is
47 /* Input: Bit in enable address to use */
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| /Documentation/core-api/ |
| D | xarray.rst | 14 resizable array. Unlike a hash, it allows you to sensibly go to the
15 next or previous entry in a cache-efficient manner. In contrast to a
16 resizable array, there is no need to copy data or change MMU mappings in
17 order to grow the array. It is more memory-efficient, parallelisable
19 RCU to perform lookups without locking.
31 nor for function pointers. You can store pointers to statically allocated
37 a value entry by calling xa_is_value(), and convert it back to
40 Some users want to tag the pointers they store in the XArray. You can
41 call xa_tag_pointer() to create an entry with a tag, xa_untag_pointer()
42 to turn a tagged entry back into an untagged pointer and xa_pointer_tag()
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| /Documentation/filesystems/iomap/ |
| D | design.rst | 5 Dumb style notes to maintain the author's sanity:
6 Please try to start sentences on separate lines so that
24 This layer tries to obtain mappings of each file ranges to storage
31 The iteration can involve mappings of file's logical offset ranges to
38 * Folio write faults to the pagecache
47 has now been extended to cover several other operations.
67 operation being performed, which enables it to combat fragmentation with
82 1. Revalidate the mapping and go back to (1) above, if necessary.
83 So far only the pagecache operations need to do this.
96 The goal of this document is to provide a brief discussion of the
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| /Documentation/mm/ |
| D | hmm.rst | 5 Provide infrastructure and helpers to integrate non-conventional memory (device
7 of this being specialized struct page for such memory (see sections 5 to 7 of
11 allowing a device to transparently access program addresses coherently with
13 for the device. This is becoming mandatory to simplify the use of advanced
14 heterogeneous computing where GPU, DSP, or FPGA are used to perform various
18 related to using device specific memory allocators. In the second section, I
19 expose the hardware limitations that are inherent to many platforms. The third
35 regular file backed memory). From here on I will refer to this aspect as split
36 address space. I use shared address space to refer to the opposite situation:
45 Concretely, this means that code that wants to leverage devices like GPUs needs
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