| /Documentation/ABI/testing/ |
| D | sysfs-class-watchdog | 5 It is a read only file. It contains status of the watchdog
6 device at boot. It is equivalent to WDIOC_GETBOOTSTATUS of
13 It is a read only file. It contains options of watchdog device.
19 It is a read only file. It contains firmware version of
26 It is a read only file. It contains identity string of
33 It is a read/write file. While reading, it gives '1'
35 it gives '0'. Writing a '1' to the file enables the
45 It is a read only file. It gives active/inactive status of
52 It is a read only file. It contains watchdog device's
53 internal status bits. It is equivalent to WDIOC_GETSTATUS
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| /Documentation/translations/it_IT/process/ |
| D | programming-language.rst | 4 :Translator: Federico Vaga <federico.vaga@vaga.pv.it>
11 Il kernel è scritto nel linguaggio di programmazione C [it-c-language]_.
12 Più precisamente, il kernel viene compilato con ``gcc`` [it-gcc]_ usando
13 l'opzione ``-std=gnu11`` [it-gcc-c-dialect-options]_: il dialetto GNU
15 Linux supporta anche ``clang`` [it-clang]_, leggete la documentazione
18 Questo dialetto contiene diverse estensioni al linguaggio [it-gnu-extensions]_,
25 [it-gcc-attribute-syntax]_. Gli attributi permettono di aggiungere una semantica,
28 linguaggio stesso (come l'aggiunta di nuove parole chiave) [it-n2049]_.
46 [it-rust-language]_ abilitando l'opzione di configurazione ``CONFIG_RUST``. Il
47 codice verrà compilato usando ``rustc`` [it-rustc]_ con l'opzione
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| /Documentation/process/ |
| D | management-style.rst | 7 on who you ask) management style for the linux kernel. It's meant to
14 to do with reality. It started as a lark, but that doesn't mean that it
17 Btw, when talking about "kernel manager", it's all about the technical
24 People", and NOT read it. Burn it, it's a great symbolic gesture.
27 making it painfully obvious to the questioner that we don't have a clue
39 manager must be to make it. That's very deep and obvious, but it's not
60 It helps to realize that the key difference between a big decision and a
75 It turns out that since nobody would be stupid enough to ever really let
76 a kernel manager have huge fiscal responsibility **anyway**, it's usually
83 you made a year ago wasn't a big decision after all, since it could be
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| /Documentation/filesystems/ |
| D | hpfs.rst | 15 is taken from it
24 Set owner/group/mode for files that do not have it specified in extended
33 - there is a list of text extensions (I thing it's better to not convert
35 change it in the source. Original readonly HPFS contained some strange
36 heuristic algorithm that I removed. I thing it's danger to let the
42 danger. I tried to write it so that it won't crash if check=normal on
44 used for debugging (for example it checks if file is allocated in
45 bitmaps when accessing it).
49 When to mark filesystem dirty so that OS/2 checks it.
72 access it under names 'a.', 'a..', 'a . . . ' etc.
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| D | path-lookup.rst | 12 It has subsequently been updated to reflect changes in the kernel
22 exploration is needed to discover, is that it is complex. There are
25 acquainted with such complexity and has tools to help manage it. One
51 It is tempting to describe the second kind as starting with a
53 slashes and components, it can be empty, in other words. This is
55 in Linux permit it when the ``AT_EMPTY_PATH`` flag is given. For
57 can execute it by calling `execveat() <execveat_>`_ passing
62 it must identify a directory that already exists, otherwise an error
66 calls interpret it quite differently (e.g. some create it, some do
67 not), but it might not even exist: neither the empty pathname nor the
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| D | configfs.rst | 22 is discovered) and it is registered with sysfs. Its attributes then
24 readdir(3)/read(2). It may allow some attributes to be modified via
30 mkdir(2). It is destroyed via rmdir(2). The attributes appear at
44 it by doing::
50 subsystems. Once a client subsystem is loaded, it will appear as a
73 write_bin_attribute method will be invoked on the final close, therefore it is
79 When an item needs to be destroyed, remove it with rmdir(2). An
80 item cannot be destroyed if any other item has a link to it (via
87 access remote block devices. Call it FakeNBD. FakeNBD uses configfs
90 the driver about it. Here's where configfs comes in.
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| D | autofs.rst | 2 autofs - how it works
59 always a regular directory, otherwise it is a mount trap when it is
69 option and particularly whether it is less than five or not.
91 the inode has S_AUTOMOUNT set, or can be set directly) then it is
95 should be mounted on the directory and to return it. The VFS is
100 automount daemon asking it to find and mount the filesystem. The
102 everything is ready. It will then return "`NULL`" indicating that the
108 reflected on the client. However it is not sufficient for autofs. As
122 to `false`. It may return one of three things:
137 autofs returns this if it detects that the process performing the
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| /Documentation/filesystems/caching/ |
| D | netfs-api.rst | 63 blob into something it can use and may employ hash tables, trees or whatever to
67 A filesystem would typically have a cookie for each inode, and would acquire it
68 in iget and relinquish it when evicting the cookie.
70 Once it has a cookie, the filesystem needs to mark the cookie as being in use.
76 unuse it in file release and it needs to use the cookie around calls to
77 truncate the cookie locally. It *also* needs to use the cookie when the
78 pagecache becomes dirty and unuse it when writeback is complete. This is
79 slightly tricky, and provision is made for it.
88 actually required and it can use the fscache I/O API directly.
95 volume it wants to access::
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| /Documentation/admin-guide/pm/ |
| D | cpuidle.rst | 20 a program is suspended and instructions belonging to it are not fetched from
25 it is an opportunity to save energy.
39 (program) from memory and executing them, but it need not work this way
43 program) at a time, it is a CPU. In that case, if the hardware is asked to
46 Second, if the processor is multi-core, each core in it is able to follow at
52 enter an idle state, that applies to the core that asked for it in the first
53 place, but it also may apply to a larger unit (say a "package" or a "cluster")
54 that the core belongs to (in fact, it may apply to an entire hierarchy of larger
57 remaining core asks the processor to enter an idle state, that may trigger it
70 by one of them, the hardware thread (or CPU) that asked for it is stopped, but
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| D | sleep-states.rst | 21 Depending on its configuration and the capabilities of the platform it runs on,
32 referred to as S2I or S2Idle). It allows more energy to be saved relative to
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
55 go back to where it left off easily enough.
60 are suspended during transitions into this state. For this reason, it should
65 reduced relative to :ref:`suspend-to-idle <s2idle>` and it may be necessary to
69 option is set and the support for it is registered by the platform with the
94 platform firmware to resume the system from it. This may be the case on other
98 relative to :ref:`suspend-to-idle <s2idle>` and :ref:`standby <standby>` and it
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| D | cpufreq.rst | 28 In some situations it is desirable or even necessary to run the program as fast
31 available). In some other cases, however, it may not be necessary to execute
33 relatively long time without utilizing it entirely may be regarded as wasteful.
34 It also may not be physically possible to maintain maximum CPU capacity for too
44 to as CPU performance scaling or CPU frequency scaling (because it involves
56 interfaces for all platforms that support CPU performance scaling. It defines
71 platform-independent form in the majority of cases, so it should be possible
79 interface it comes from and may not be easily represented in an abstract,
90 control the P-state of multiple CPUs at the same time and writing to it affects
111 It is only possible to register one scaling driver at a time, so the scaling
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| /Documentation/userspace-api/media/dvb/ |
| D | frontend-stat-properties.rst | 16 It should be noted, however, that new OFDM delivery systems like ISDB
36 - ``scale`` - Scale for the value. It can be:
39 frontend, but it was not possible to collect it (could be a
63 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
82 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
103 In order to get the BER (Bit Error Rate) measurement, it should be
108 bit count measurements. The frontend may reset it when a
113 - ``FE_SCALE_NOT_AVAILABLE`` - it failed to measure it, or the
130 It should be noted that this measurement can be smaller than the total
136 bit count measurements. The frontend may reset it when a
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| /Documentation/security/keys/ |
| D | request-key.rst | 46 does not need to link the key to a keyring to prevent it from being immediately
48 it's up to the caller to destroy the key.
50 The request_key_tag() call is like the in-kernel request_key(), except that it
59 The request_key_rcu() call is like the request_key_tag() call, except that it
82 a suitable key there. If there is, it returns the key. If there isn't,
86 3) request_key() sees that A doesn't have the desired key yet, so it creates
104 Kerberos TGT key). It just requests the appropriate key, and the keyring
107 This will permit it to then search the keyrings of process A with the
108 UID, GID, groups and security info of process A as if it was process A,
111 8) The program then does what it must to get the data with which to
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| /Documentation/driver-api/usb/ |
| D | persist.rst | 20 required to behave as though the device has been unplugged. It's a
23 device is still attached or perhaps it was removed and a different
29 though they had disconnected. This is always safe and it is the
35 system woke up, who cares? It'll still work the same when you type on
36 it.
52 it's as though you had unplugged all the USB devices. Yes, it's
64 the system can't be suspended at all. (All right, it _can_ be
65 suspended -- but it will crash as soon as it wakes up, which isn't
72 The kernel includes a feature called USB-persist. It tries to work
76 It works like this. If the kernel sees that a USB host controller is
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| /Documentation/power/ |
| D | s2ram.rst | 13 simple module unload can fix it.
21 always it's a driver that is buggy. Thank God for the suspend/resume
23 way to debug these things, and it's actually pretty powerful (but
41 - if it doesn't come back up (which is usually the problem), reboot by
52 fix it, disable it, or trace into its resume function.
62 used to run with "radeonfb" (it's an ATI Radeon mobility). It turns out
63 that "radeonfb" simply cannot resume that device - it tries to set the
64 PLL's, and it just _hangs_. Using the regular VGA console and letting X
65 resume it instead works fine.
74 pm_trace is not compatible with asynchronous suspend, so it turns
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| D | swsusp.rst | 21 it may cause some problems, too. If you change kernel command line
22 between suspend and resume, it may do something wrong. If you change
23 your hardware while system is suspended... well, it was not good idea;
24 but it will probably only crash.
26 ( ) suspend/resume support is needed to make it safe.
36 line or specify it using /sys/power/resume.
40 resume_offset=<number> on the kernel command line or specify it
52 to RAM (provided your platform supports it), you can try::
66 before suspend (it is limited to around 2/5 of available RAM by default).
69 if found, it then checks the contents for the hibernation image signature.
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| D | pci.rst | 34 Usually, a device is put into a low-power state when it is underutilized or
35 completely inactive. However, when it is necessary to use the device once
36 again, it has to be put back into the "fully functional" state (full-power
53 to put the device that sent it into the full-power state. However, the PCI Bus
56 It is assumed that the platform firmware will perform this task and therefore,
57 even though a PCI device is set up to generate PMEs, it also may be necessary to
63 preparing the device to generate wakeup signals. In that case, however, it
75 introduced between the PCI 2.1 and PCI 2.2 Specifications. It defined a
80 but it is mandatory for PCI Express devices. If a device supports the PCI PM
81 Spec, it has an 8 byte power management capability field in its PCI
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| /Documentation/scsi/ |
| D | qlogicfas.rst | 21 Nor does it support the PCI-Basic, which is supported by the
34 the Linux PCMCIA driver, you will have to adjust it or otherwise stop
35 it from configuring the card.
37 I am working with the PCMCIA group to make it more flexible, but that
44 configuration. As shipped, it provides a balance between speed and
49 It may be a good idea to enable RESET_AT_START, especially if the
52 command or something. It comes up faster if this is set to zero, and
53 if you have reliable hardware and connections it may be more useful to
59 Make sure it works properly under DOS. You should also do an initial FDISK
70 large executable or archive). It should be at least 5 megabytes, but
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| /Documentation/filesystems/xfs/ |
| D | xfs-self-describing-metadata.rst | 14 adequate for supporting PB scale filesystems with billions of inodes, however it
24 For example, it is entirely possible to manually use xfs_db and a bit of
26 determine the root cause of a corruption problem, but it is still mainly a
28 weren't the ultimate cause of a corruption event. It may take a few hours to a
44 magic number in the metadata block, we have no other way of identifying what it
45 is supposed to be. We can't even identify if it is the right place. Put simply,
46 you can't look at a single metadata block in isolation and say "yes, it is
54 went wrong, but it is impossible to tell what order the blocks were linked into
74 numbers in the metadata objects. That is, if it has the current magic number,
75 the metadata isn't self identifying. If it contains a new magic number, it is
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| /Documentation/admin-guide/device-mapper/ |
| D | vdo-design.rst | 11 Corp. starting in 2009. It was first released in 2013 and has been used in
12 production environments ever since. It was made open-source in 2017 after
17 vdo target has a maximum block size of 4K. However, it can achieve
19 reference a single 4K of actual storage. It can achieve compression rates
54 each zone has an implicit lock on the structures it manages for all its
70 have temporal locality. When a duplicate appears, it is more likely that
74 duplicate recent data than it is to duplicate older data and in general,
76 when the index is full, it should cull its oldest records to make space for
80 those savings, vdo does not attempt to find every last duplicate block. It
85 that data on the underlying storage. However, it is not possible to
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| /Documentation/fb/ |
| D | matroxfb.rst | 13 * It provides a nice large console (128 cols + 48 lines with 1024x768)
24 How to use it?
93 XF{68,86}_FBDev should work just fine, but it is non-accelerated. On non-intel
108 Driver contains SVGALib compatibility code. It is turned on by choosing textual
109 mode for console. You can do it at boot time by using videomode
112 Switching to another console and back fixes it. I hope that it is SVGALib's
127 it always probe for memory. Default is to use whole detected
132 configuration, you can override it by this (you cannot override
133 `off`). It is default.
134 noaccel do not use acceleration engine. It does not work on Alphas.
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| /Documentation/admin-guide/mm/ |
| D | multigen_lru.rst | 9 memory. It directly impacts the kswapd CPU usage and RAM efficiency.
40 batches, when MMU sets it (e.g., on x86). This behavior can
41 theoretically worsen lock contention (mmap_lock). If it is
47 well, when MMU sets it (e.g., on x86). This behavior was not
48 verified on x86 varieties other than Intel and AMD. If it is
66 Personal computers are more sensitive to thrashing because it can
74 option works as an adjustable pressure relief valve, and when open, it
97 in a given time interval, and it is usually done with little impact on
101 each server it manages can allocate a certain amount of memory for
102 this new job before it can pick a candidate. To do so, the job
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| /Documentation/driver-api/pm/ |
| D | cpuidle.rst | 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
23 depended on by it into an idle state in which they will draw less power.
26 situation in principle, so it may be necessary to find the most suitable one
33 or platform design details in it is separate from the code that interacts with
34 the hardware. It generally is divided into three categories of functional
55 below, and a name (string) used for identifying it.
59 a pointer to it passed as the argument. If successful, that causes the core to
60 add the governor to the global list of available governors and, if it is the
69 Once registered, ``CPUIdle`` governors cannot be unregistered, so it is not
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| /Documentation/hwmon/ |
| D | submitting-patches.rst | 12 * It should be unnecessary to mention, but please read and follow:
29 and a consistent coding style makes it easier for others to understand
35 architecture. If run-time testing was not achieved, it should be written
39 CONFIG_SMP, make sure it compiles for all configuration variants.
51 your patch into a cleanup part and the actual addition. This makes it easier
61 formatting is clean. If unsure about formatting in your new driver, run it
63 cleanup, but it is a good start.
79 * Avoid macros to generate groups of sensor attributes. It not only confuses
80 checkpatch, but also makes it more difficult to review the code.
83 may save a line or so in the source, it obfuscates the code and makes code
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| /Documentation/driver-api/driver-model/ |
| D | binding.rst | 6 driver that can control it. Bus drivers have typically handled this
16 type in the system. When device_register is called for a device, it is
19 for a driver, it is inserted at the end of this list. These are the
27 to find one that supports it. In order to determine that, the device
31 algorithm, it is up to the bus driver to provide a callback to compare
39 chance to verify that it really does support the hardware, and that
40 it's in a working state.
46 the class to which it belongs. Device drivers belong to one and only one
49 and actually register it with the class, which happens with the
91 When a device is removed, the reference count for it will eventually
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