diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/crypto/async-tx-api.txt | 219 | ||||
| -rw-r--r-- | Documentation/devices.txt | 2 | ||||
| -rw-r--r-- | Documentation/input/iforce-protocol.txt | 508 | ||||
| -rw-r--r-- | Documentation/kernel-parameters.txt | 20 | ||||
| -rw-r--r-- | Documentation/lguest/lguest.c | 2 | ||||
| -rw-r--r-- | Documentation/lockstat.txt | 120 | ||||
| -rw-r--r-- | Documentation/sysrq.txt | 2 |
7 files changed, 607 insertions, 266 deletions
diff --git a/Documentation/crypto/async-tx-api.txt b/Documentation/crypto/async-tx-api.txt new file mode 100644 index 0000000..c1e9545 --- /dev/null +++ b/Documentation/crypto/async-tx-api.txt @@ -0,0 +1,219 @@ + Asynchronous Transfers/Transforms API + +1 INTRODUCTION + +2 GENEALOGY + +3 USAGE +3.1 General format of the API +3.2 Supported operations +3.3 Descriptor management +3.4 When does the operation execute? +3.5 When does the operation complete? +3.6 Constraints +3.7 Example + +4 DRIVER DEVELOPER NOTES +4.1 Conformance points +4.2 "My application needs finer control of hardware channels" + +5 SOURCE + +--- + +1 INTRODUCTION + +The async_tx API provides methods for describing a chain of asynchronous +bulk memory transfers/transforms with support for inter-transactional +dependencies. It is implemented as a dmaengine client that smooths over +the details of different hardware offload engine implementations. Code +that is written to the API can optimize for asynchronous operation and +the API will fit the chain of operations to the available offload +resources. + +2 GENEALOGY + +The API was initially designed to offload the memory copy and +xor-parity-calculations of the md-raid5 driver using the offload engines +present in the Intel(R) Xscale series of I/O processors. It also built +on the 'dmaengine' layer developed for offloading memory copies in the +network stack using Intel(R) I/OAT engines. The following design +features surfaced as a result: +1/ implicit synchronous path: users of the API do not need to know if + the platform they are running on has offload capabilities. The + operation will be offloaded when an engine is available and carried out + in software otherwise. +2/ cross channel dependency chains: the API allows a chain of dependent + operations to be submitted, like xor->copy->xor in the raid5 case. The + API automatically handles cases where the transition from one operation + to another implies a hardware channel switch. +3/ dmaengine extensions to support multiple clients and operation types + beyond 'memcpy' + +3 USAGE + +3.1 General format of the API: +struct dma_async_tx_descriptor * +async_<operation>(<op specific parameters>, + enum async_tx_flags flags, + struct dma_async_tx_descriptor *dependency, + dma_async_tx_callback callback_routine, + void *callback_parameter); + +3.2 Supported operations: +memcpy - memory copy between a source and a destination buffer +memset - fill a destination buffer with a byte value +xor - xor a series of source buffers and write the result to a + destination buffer +xor_zero_sum - xor a series of source buffers and set a flag if the + result is zero. The implementation attempts to prevent + writes to memory + +3.3 Descriptor management: +The return value is non-NULL and points to a 'descriptor' when the operation +has been queued to execute asynchronously. Descriptors are recycled +resources, under control of the offload engine driver, to be reused as +operations complete. When an application needs to submit a chain of +operations it must guarantee that the descriptor is not automatically recycled +before the dependency is submitted. This requires that all descriptors be +acknowledged by the application before the offload engine driver is allowed to +recycle (or free) the descriptor. A descriptor can be acked by one of the +following methods: +1/ setting the ASYNC_TX_ACK flag if no child operations are to be submitted +2/ setting the ASYNC_TX_DEP_ACK flag to acknowledge the parent + descriptor of a new operation. +3/ calling async_tx_ack() on the descriptor. + +3.4 When does the operation execute? +Operations do not immediately issue after return from the +async_<operation> call. Offload engine drivers batch operations to +improve performance by reducing the number of mmio cycles needed to +manage the channel. Once a driver-specific threshold is met the driver +automatically issues pending operations. An application can force this +event by calling async_tx_issue_pending_all(). This operates on all +channels since the application has no knowledge of channel to operation +mapping. + +3.5 When does the operation complete? +There are two methods for an application to learn about the completion +of an operation. +1/ Call dma_wait_for_async_tx(). This call causes the CPU to spin while + it polls for the completion of the operation. It handles dependency + chains and issuing pending operations. +2/ Specify a completion callback. The callback routine runs in tasklet + context if the offload engine driver supports interrupts, or it is + called in application context if the operation is carried out + synchronously in software. The callback can be set in the call to + async_<operation>, or when the application needs to submit a chain of + unknown length it can use the async_trigger_callback() routine to set a + completion interrupt/callback at the end of the chain. + +3.6 Constraints: +1/ Calls to async_<operation> are not permitted in IRQ context. Other + contexts are permitted provided constraint #2 is not violated. +2/ Completion callback routines cannot submit new operations. This + results in recursion in the synchronous case and spin_locks being + acquired twice in the asynchronous case. + +3.7 Example: +Perform a xor->copy->xor operation where each operation depends on the +result from the previous operation: + +void complete_xor_copy_xor(void *param) +{ + printk("complete\n"); +} + +int run_xor_copy_xor(struct page **xor_srcs, + int xor_src_cnt, + struct page *xor_dest, + size_t xor_len, + struct page *copy_src, + struct page *copy_dest, + size_t copy_len) +{ + struct dma_async_tx_descriptor *tx; + + tx = async_xor(xor_dest, xor_srcs, 0, xor_src_cnt, xor_len, + ASYNC_TX_XOR_DROP_DST, NULL, NULL, NULL); + tx = async_memcpy(copy_dest, copy_src, 0, 0, copy_len, + ASYNC_TX_DEP_ACK, tx, NULL, NULL); + tx = async_xor(xor_dest, xor_srcs, 0, xor_src_cnt, xor_len, + ASYNC_TX_XOR_DROP_DST | ASYNC_TX_DEP_ACK | ASYNC_TX_ACK, + tx, complete_xor_copy_xor, NULL); + + async_tx_issue_pending_all(); +} + +See include/linux/async_tx.h for more information on the flags. See the +ops_run_* and ops_complete_* routines in drivers/md/raid5.c for more +implementation examples. + +4 DRIVER DEVELOPMENT NOTES +4.1 Conformance points: +There are a few conformance points required in dmaengine drivers to +accommodate assumptions made by applications using the async_tx API: +1/ Completion callbacks are expected to happen in tasklet context +2/ dma_async_tx_descriptor fields are never manipulated in IRQ context +3/ Use async_tx_run_dependencies() in the descriptor clean up path to + handle submission of dependent operations + +4.2 "My application needs finer control of hardware channels" +This requirement seems to arise from cases where a DMA engine driver is +trying to support device-to-memory DMA. The dmaengine and async_tx +implementations were designed for offloading memory-to-memory +operations; however, there are some capabilities of the dmaengine layer +that can be used for platform-specific channel management. +Platform-specific constraints can be handled by registering the +application as a 'dma_client' and implementing a 'dma_event_callback' to +apply a filter to the available channels in the system. Before showing +how to implement a custom dma_event callback some background of +dmaengine's client support is required. + +The following routines in dmaengine support multiple clients requesting +use of a channel: +- dma_async_client_register(struct dma_client *client) +- dma_async_client_chan_request(struct dma_client *client) + +dma_async_client_register takes a pointer to an initialized dma_client +structure. It expects that the 'event_callback' and 'cap_mask' fields +are already initialized. + +dma_async_client_chan_request triggers dmaengine to notify the client of +all channels that satisfy the capability mask. It is up to the client's +event_callback routine to track how many channels the client needs and +how many it is currently using. The dma_event_callback routine returns a +dma_state_client code to let dmaengine know the status of the +allocation. + +Below is the example of how to extend this functionality for +platform-specific filtering of the available channels beyond the +standard capability mask: + +static enum dma_state_client +my_dma_client_callback(struct dma_client *client, + struct dma_chan *chan, enum dma_state state) +{ + struct dma_device *dma_dev; + struct my_platform_specific_dma *plat_dma_dev; + + dma_dev = chan->device; + plat_dma_dev = container_of(dma_dev, + struct my_platform_specific_dma, + dma_dev); + + if (!plat_dma_dev->platform_specific_capability) + return DMA_DUP; + + . . . +} + +5 SOURCE +include/linux/dmaengine.h: core header file for DMA drivers and clients +drivers/dma/dmaengine.c: offload engine channel management routines +drivers/dma/: location for offload engine drivers +include/linux/async_tx.h: core header file for the async_tx api +crypto/async_tx/async_tx.c: async_tx interface to dmaengine and common code +crypto/async_tx/async_memcpy.c: copy offload +crypto/async_tx/async_memset.c: memory fill offload +crypto/async_tx/async_xor.c: xor and xor zero sum offload diff --git a/Documentation/devices.txt b/Documentation/devices.txt index 8de132a..6c46730 100644 --- a/Documentation/devices.txt +++ b/Documentation/devices.txt @@ -94,6 +94,8 @@ Your cooperation is appreciated. 9 = /dev/urandom Faster, less secure random number gen. 10 = /dev/aio Asynchronous I/O notification interface 11 = /dev/kmsg Writes to this come out as printk's + 12 = /dev/oldmem Used by crashdump kernels to access + the memory of the kernel that crashed. 1 block RAM disk 0 = /dev/ram0 First RAM disk diff --git a/Documentation/input/iforce-protocol.txt b/Documentation/input/iforce-protocol.txt index 95df4ca..8777d2d 100644 --- a/Documentation/input/iforce-protocol.txt +++ b/Documentation/input/iforce-protocol.txt @@ -1,254 +1,254 @@ -** Introduction
-This document describes what I managed to discover about the protocol used to
-specify force effects to I-Force 2.0 devices. None of this information comes
-from Immerse. That's why you should not trust what is written in this
-document. This document is intended to help understanding the protocol.
-This is not a reference. Comments and corrections are welcome. To contact me,
-send an email to: deneux@ifrance.com
-
-** WARNING **
-I may not be held responsible for any dammage or harm caused if you try to
-send data to your I-Force device based on what you read in this document.
-
-** Preliminary Notes:
-All values are hexadecimal with big-endian encoding (msb on the left). Beware,
-values inside packets are encoded using little-endian. Bytes whose roles are
-unknown are marked ??? Information that needs deeper inspection is marked (?)
-
-** General form of a packet **
-This is how packets look when the device uses the rs232 to communicate.
-2B OP LEN DATA CS
-CS is the checksum. It is equal to the exclusive or of all bytes.
-
-When using USB:
-OP DATA
-The 2B, LEN and CS fields have disappeared, probably because USB handles frames and
-data corruption is handled or unsignificant.
-
-First, I describe effects that are sent by the device to the computer
-
-** Device input state
-This packet is used to indicate the state of each button and the value of each
-axis
-OP= 01 for a joystick, 03 for a wheel
-LEN= Varies from device to device
-00 X-Axis lsb
-01 X-Axis msb
-02 Y-Axis lsb, or gas pedal for a wheel
-03 Y-Axis msb, or brake pedal for a wheel
-04 Throttle
-05 Buttons
-06 Lower 4 bits: Buttons
- Upper 4 bits: Hat
-07 Rudder
-
-** Device effects states
-OP= 02
-LEN= Varies
-00 ? Bit 1 (Value 2) is the value of the deadman switch
-01 Bit 8 is set if the effect is playing. Bits 0 to 7 are the effect id.
-02 ??
-03 Address of parameter block changed (lsb)
-04 Address of parameter block changed (msb)
-05 Address of second parameter block changed (lsb)
-... depending on the number of parameter blocks updated
-
-** Force effect **
-OP= 01
-LEN= 0e
-00 Channel (when playing several effects at the same time, each must be assigned a channel)
-01 Wave form
- Val 00 Constant
- Val 20 Square
- Val 21 Triangle
- Val 22 Sine
- Val 23 Sawtooth up
- Val 24 Sawtooth down
- Val 40 Spring (Force = f(pos))
- Val 41 Friction (Force = f(velocity)) and Inertia (Force = f(acceleration))
-
-
-02 Axes affected and trigger
- Bits 4-7: Val 2 = effect along one axis. Byte 05 indicates direction
- Val 4 = X axis only. Byte 05 must contain 5a
- Val 8 = Y axis only. Byte 05 must contain b4
- Val c = X and Y axes. Bytes 05 must contain 60
- Bits 0-3: Val 0 = No trigger
- Val x+1 = Button x triggers the effect
- When the whole byte is 0, cancel the previously set trigger
-
-03-04 Duration of effect (little endian encoding, in ms)
-
-05 Direction of effect, if applicable. Else, see 02 for value to assign.
-
-06-07 Minimum time between triggering.
-
-08-09 Address of periodicity or magnitude parameters
-0a-0b Address of attack and fade parameters, or ffff if none.
-*or*
-08-09 Address of interactive parameters for X-axis, or ffff if not applicable
-0a-0b Address of interactive parameters for Y-axis, or ffff if not applicable
-
-0c-0d Delay before execution of effect (little endian encoding, in ms)
-
-
-** Time based parameters **
-
-*** Attack and fade ***
-OP= 02
-LEN= 08
-00-01 Address where to store the parameteres
-02-03 Duration of attack (little endian encoding, in ms)
-04 Level at end of attack. Signed byte.
-05-06 Duration of fade.
-07 Level at end of fade.
-
-*** Magnitude ***
-OP= 03
-LEN= 03
-00-01 Address
-02 Level. Signed byte.
-
-*** Periodicity ***
-OP= 04
-LEN= 07
-00-01 Address
-02 Magnitude. Signed byte.
-03 Offset. Signed byte.
-04 Phase. Val 00 = 0 deg, Val 40 = 90 degs.
-05-06 Period (little endian encoding, in ms)
-
-** Interactive parameters **
-OP= 05
-LEN= 0a
-00-01 Address
-02 Positive Coeff
-03 Negative Coeff
-04+05 Offset (center)
-06+07 Dead band (Val 01F4 = 5000 (decimal))
-08 Positive saturation (Val 0a = 1000 (decimal) Val 64 = 10000 (decimal))
-09 Negative saturation
-
-The encoding is a bit funny here: For coeffs, these are signed values. The
-maximum value is 64 (100 decimal), the min is 9c.
-For the offset, the minimum value is FE0C, the maximum value is 01F4.
-For the deadband, the minimum value is 0, the max is 03E8.
-
-** Controls **
-OP= 41
-LEN= 03
-00 Channel
-01 Start/Stop
- Val 00: Stop
- Val 01: Start and play once.
- Val 41: Start and play n times (See byte 02 below)
-02 Number of iterations n.
-
-** Init **
-
-*** Querying features ***
-OP= ff
-Query command. Length varies according to the query type.
-The general format of this packet is:
-ff 01 QUERY [INDEX] CHECKSUM
-reponses are of the same form:
-FF LEN QUERY VALUE_QUERIED CHECKSUM2
-where LEN = 1 + length(VALUE_QUERIED)
-
-**** Query ram size ****
-QUERY = 42 ('B'uffer size)
-The device should reply with the same packet plus two additionnal bytes
-containing the size of the memory:
-ff 03 42 03 e8 CS would mean that the device has 1000 bytes of ram available.
-
-**** Query number of effects ****
-QUERY = 4e ('N'umber of effects)
-The device should respond by sending the number of effects that can be played
-at the same time (one byte)
-ff 02 4e 14 CS would stand for 20 effects.
-
-**** Vendor's id ****
-QUERY = 4d ('M'anufacturer)
-Query the vendors'id (2 bytes)
-
-**** Product id *****
-QUERY = 50 ('P'roduct)
-Query the product id (2 bytes)
-
-**** Open device ****
-QUERY = 4f ('O'pen)
-No data returned.
-
-**** Close device *****
-QUERY = 43 ('C')lose
-No data returned.
-
-**** Query effect ****
-QUERY = 45 ('E')
-Send effect type.
-Returns nonzero if supported (2 bytes)
-
-**** Firmware Version ****
-QUERY = 56 ('V'ersion)
-Sends back 3 bytes - major, minor, subminor
-
-*** Initialisation of the device ***
-
-**** Set Control ****
-!!! Device dependent, can be different on different models !!!
-OP= 40 <idx> <val> [<val>]
-LEN= 2 or 3
-00 Idx
- Idx 00 Set dead zone (0..2048)
- Idx 01 Ignore Deadman sensor (0..1)
- Idx 02 Enable comm watchdog (0..1)
- Idx 03 Set the strength of the spring (0..100)
- Idx 04 Enable or disable the spring (0/1)
- Idx 05 Set axis saturation threshold (0..2048)
-
-**** Set Effect State ****
-OP= 42 <val>
-LEN= 1
-00 State
- Bit 3 Pause force feedback
- Bit 2 Enable force feedback
- Bit 0 Stop all effects
-
-**** Set overall gain ****
-OP= 43 <val>
-LEN= 1
-00 Gain
- Val 00 = 0%
- Val 40 = 50%
- Val 80 = 100%
-
-** Parameter memory **
-
-Each device has a certain amount of memory to store parameters of effects.
-The amount of RAM may vary, I encountered values from 200 to 1000 bytes. Below
-is the amount of memory apparently needed for every set of parameters:
- - period : 0c
- - magnitude : 02
- - attack and fade : 0e
- - interactive : 08
-
-** Appendix: How to study the protocol ? **
-
-1. Generate effects using the force editor provided with the DirectX SDK, or use Immersion Studio (freely available at their web site in the developer section: www.immersion.com)
-2. Start a soft spying RS232 or USB (depending on where you connected your joystick/wheel). I used ComPortSpy from fCoder (alpha version!)
-3. Play the effect, and watch what happens on the spy screen.
-
-A few words about ComPortSpy:
-At first glance, this soft seems, hum, well... buggy. In fact, data appear with a few seconds latency. Personnaly, I restart it every time I play an effect.
-Remember it's free (as in free beer) and alpha!
-
-** URLS **
-Check www.immerse.com for Immersion Studio, and www.fcoder.com for ComPortSpy.
-
-** Author of this document **
-Johann Deneux <deneux@ifrance.com>
-Home page at http://www.esil.univ-mrs.fr/~jdeneux/projects/ff/
-
-Additions by Vojtech Pavlik.
-
-I-Force is trademark of Immersion Corp.
+** Introduction +This document describes what I managed to discover about the protocol used to +specify force effects to I-Force 2.0 devices. None of this information comes +from Immerse. That's why you should not trust what is written in this +document. This document is intended to help understanding the protocol. +This is not a reference. Comments and corrections are welcome. To contact me, +send an email to: deneux@ifrance.com + +** WARNING ** +I may not be held responsible for any dammage or harm caused if you try to +send data to your I-Force device based on what you read in this document. + +** Preliminary Notes: +All values are hexadecimal with big-endian encoding (msb on the left). Beware, +values inside packets are encoded using little-endian. Bytes whose roles are +unknown are marked ??? Information that needs deeper inspection is marked (?) + +** General form of a packet ** +This is how packets look when the device uses the rs232 to communicate. +2B OP LEN DATA CS +CS is the checksum. It is equal to the exclusive or of all bytes. + +When using USB: +OP DATA +The 2B, LEN and CS fields have disappeared, probably because USB handles frames and +data corruption is handled or unsignificant. + +First, I describe effects that are sent by the device to the computer + +** Device input state +This packet is used to indicate the state of each button and the value of each +axis +OP= 01 for a joystick, 03 for a wheel +LEN= Varies from device to device +00 X-Axis lsb +01 X-Axis msb +02 Y-Axis lsb, or gas pedal for a wheel +03 Y-Axis msb, or brake pedal for a wheel +04 Throttle +05 Buttons +06 Lower 4 bits: Buttons + Upper 4 bits: Hat +07 Rudder + +** Device effects states +OP= 02 +LEN= Varies +00 ? Bit 1 (Value 2) is the value of the deadman switch +01 Bit 8 is set if the effect is playing. Bits 0 to 7 are the effect id. +02 ?? +03 Address of parameter block changed (lsb) +04 Address of parameter block changed (msb) +05 Address of second parameter block changed (lsb) +... depending on the number of parameter blocks updated + +** Force effect ** +OP= 01 +LEN= 0e +00 Channel (when playing several effects at the same time, each must be assigned a channel) +01 Wave form + Val 00 Constant + Val 20 Square + Val 21 Triangle + Val 22 Sine + Val 23 Sawtooth up + Val 24 Sawtooth down + Val 40 Spring (Force = f(pos)) + Val 41 Friction (Force = f(velocity)) and Inertia (Force = f(acceleration)) + + +02 Axes affected and trigger + Bits 4-7: Val 2 = effect along one axis. Byte 05 indicates direction + Val 4 = X axis only. Byte 05 must contain 5a + Val 8 = Y axis only. Byte 05 must contain b4 + Val c = X and Y axes. Bytes 05 must contain 60 + Bits 0-3: Val 0 = No trigger + Val x+1 = Button x triggers the effect + When the whole byte is 0, cancel the previously set trigger + +03-04 Duration of effect (little endian encoding, in ms) + +05 Direction of effect, if applicable. Else, see 02 for value to assign. + +06-07 Minimum time between triggering. + +08-09 Address of periodicity or magnitude parameters +0a-0b Address of attack and fade parameters, or ffff if none. +*or* +08-09 Address of interactive parameters for X-axis, or ffff if not applicable +0a-0b Address of interactive parameters for Y-axis, or ffff if not applicable + +0c-0d Delay before execution of effect (little endian encoding, in ms) + + +** Time based parameters ** + +*** Attack and fade *** +OP= 02 +LEN= 08 +00-01 Address where to store the parameteres +02-03 Duration of attack (little endian encoding, in ms) +04 Level at end of attack. Signed byte. +05-06 Duration of fade. +07 Level at end of fade. + +*** Magnitude *** +OP= 03 +LEN= 03 +00-01 Address +02 Level. Signed byte. + +*** Periodicity *** +OP= 04 +LEN= 07 +00-01 Address +02 Magnitude. Signed byte. +03 Offset. Signed byte. +04 Phase. Val 00 = 0 deg, Val 40 = 90 degs. +05-06 Period (little endian encoding, in ms) + +** Interactive parameters ** +OP= 05 +LEN= 0a +00-01 Address +02 Positive Coeff +03 Negative Coeff +04+05 Offset (center) +06+07 Dead band (Val 01F4 = 5000 (decimal)) +08 Positive saturation (Val 0a = 1000 (decimal) Val 64 = 10000 (decimal)) +09 Negative saturation + +The encoding is a bit funny here: For coeffs, these are signed values. The +maximum value is 64 (100 decimal), the min is 9c. +For the offset, the minimum value is FE0C, the maximum value is 01F4. +For the deadband, the minimum value is 0, the max is 03E8. + +** Controls ** +OP= 41 +LEN= 03 +00 Channel +01 Start/Stop + Val 00: Stop + Val 01: Start and play once. + Val 41: Start and play n times (See byte 02 below) +02 Number of iterations n. + +** Init ** + +*** Querying features *** +OP= ff +Query command. Length varies according to the query type. +The general format of this packet is: +ff 01 QUERY [INDEX] CHECKSUM +reponses are of the same form: +FF LEN QUERY VALUE_QUERIED CHECKSUM2 +where LEN = 1 + length(VALUE_QUERIED) + +**** Query ram size **** +QUERY = 42 ('B'uffer size) +The device should reply with the same packet plus two additionnal bytes +containing the size of the memory: +ff 03 42 03 e8 CS would mean that the device has 1000 bytes of ram available. + +**** Query number of effects **** +QUERY = 4e ('N'umber of effects) +The device should respond by sending the number of effects that can be played +at the same time (one byte) +ff 02 4e 14 CS would stand for 20 effects. + +**** Vendor's id **** +QUERY = 4d ('M'anufacturer) +Query the vendors'id (2 bytes) + +**** Product id ***** +QUERY = 50 ('P'roduct) +Query the product id (2 bytes) + +**** Open device **** +QUERY = 4f ('O'pen) +No data returned. + +**** Close device ***** +QUERY = 43 ('C')lose +No data returned. + +**** Query effect **** +QUERY = 45 ('E') +Send effect type. +Returns nonzero if supported (2 bytes) + +**** Firmware Version **** +QUERY = 56 ('V'ersion) +Sends back 3 bytes - major, minor, subminor + +*** Initialisation of the device *** + +**** Set Control **** +!!! Device dependent, can be different on different models !!! +OP= 40 <idx> <val> [<val>] +LEN= 2 or 3 +00 Idx + Idx 00 Set dead zone (0..2048) + Idx 01 Ignore Deadman sensor (0..1) + Idx 02 Enable comm watchdog (0..1) + Idx 03 Set the strength of the spring (0..100) + Idx 04 Enable or disable the spring (0/1) + Idx 05 Set axis saturation threshold (0..2048) + +**** Set Effect State **** +OP= 42 <val> +LEN= 1 +00 State + Bit 3 Pause force feedback + Bit 2 Enable force feedback + Bit 0 Stop all effects + +**** Set overall gain **** +OP= 43 <val> +LEN= 1 +00 Gain + Val 00 = 0% + Val 40 = 50% + Val 80 = 100% + +** Parameter memory ** + +Each device has a certain amount of memory to store parameters of effects. +The amount of RAM may vary, I encountered values from 200 to 1000 bytes. Below +is the amount of memory apparently needed for every set of parameters: + - period : 0c + - magnitude : 02 + - attack and fade : 0e + - interactive : 08 + +** Appendix: How to study the protocol ? ** + +1. Generate effects using the force editor provided with the DirectX SDK, or use Immersion Studio (freely available at their web site in the developer section: www.immersion.com) +2. Start a soft spying RS232 or USB (depending on where you connected your joystick/wheel). I used ComPortSpy from fCoder (alpha version!) +3. Play the effect, and watch what happens on the spy screen. + +A few words about ComPortSpy: +At first glance, this soft seems, hum, well... buggy. In fact, data appear with a few seconds latency. Personnaly, I restart it every time I play an effect. +Remember it's free (as in free beer) and alpha! + +** URLS ** +Check www.immerse.com for Immersion Studio, and www.fcoder.com for ComPortSpy. + +** Author of this document ** +Johann Deneux <deneux@ifrance.com> +Home page at http://www.esil.univ-mrs.fr/~jdeneux/projects/ff/ + +Additions by Vojtech Pavlik. + +I-Force is trademark of Immersion Corp. diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 586b6f8..4d175c7 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1,5 +1,5 @@ - Kernel Parameters - ~~~~~~~~~~~~~~~~~ + Kernel Parameters + ~~~~~~~~~~~~~~~~~ The following is a consolidated list of the kernel parameters as implemented (mostly) by the __setup() macro and sorted into English Dictionary order @@ -1462,7 +1462,7 @@ and is between 256 and 4096 characters. It is defined in the file reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode Format: <reboot_mode>[,<reboot_mode2>[,...]] - See arch/*/kernel/reboot.c or arch/*/kernel/process.c + See arch/*/kernel/reboot.c or arch/*/kernel/process.c reserve= [KNL,BUGS] Force the kernel to ignore some iomem area @@ -1550,12 +1550,12 @@ and is between 256 and 4096 characters. It is defined in the file selinux_compat_net = [SELINUX] Set initial selinux_compat_net flag value. - Format: { "0" | "1" } - 0 -- use new secmark-based packet controls - 1 -- use legacy packet controls - Default value is 0 (preferred). - Value can be changed at runtime via - /selinux/compat_net. + Format: { "0" | "1" } + 0 -- use new secmark-based packet controls + 1 -- use legacy packet controls + Default value is 0 (preferred). + Value can be changed at runtime via + /selinux/compat_net. serialnumber [BUGS=X86-32] @@ -1954,7 +1954,7 @@ and is between 256 and 4096 characters. It is defined in the file norandmaps Don't use address space randomization Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space - unwind_debug=N N > 0 will enable dwarf2 unwinder debugging + unwind_debug=N N > 0 will enable dwarf2 unwinder debugging This is useful to get more information why you got a "dwarf2 unwinder stuck" diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index f791840..73c5f1f 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -882,7 +882,7 @@ static u32 handle_block_output(int fd, const struct iovec *iov, * of the block file (possibly extending it). */ if (off + len > device_len) { /* Trim it back to the correct length */ - ftruncate(dev->fd, device_len); + ftruncate64(dev->fd, device_len); /* Die, bad Guest, die. */ errx(1, "Write past end %llu+%u", off, len); } diff --git a/Documentation/lockstat.txt b/Documentation/lockstat.txt new file mode 100644 index 0000000..4ba4664 --- /dev/null +++ b/Documentation/lockstat.txt @@ -0,0 +1,120 @@ + +LOCK STATISTICS + +- WHAT + +As the name suggests, it provides statistics on locks. + +- WHY + +Because things like lock contention can severely impact performance. + +- HOW + +Lockdep already has hooks in the lock functions and maps lock instances to +lock classes. We build on that. The graph below shows the relation between +the lock functions and the various hooks therein. + + __acquire + | + lock _____ + | \ + | __contended + | | + | <wait> + | _______/ + |/ + | + __acquired + | + . + <hold> + . + | + __release + | + unlock + +lock, unlock - the regular lock functions +__* - the hooks +<> - states + +With these hooks we provide the following statistics: + + con-bounces - number of lock contention that involved x-cpu data + contentions - number of lock acquisitions that had to wait + wait time min - shortest (non-0) time we ever had to wait for a lock + max - longest time we ever had to wait for a lock + total - total time we spend waiting on this lock + acq-bounces - number of lock acquisitions that involved x-cpu data + acquisitions - number of times we took the lock + hold time min - shortest (non-0) time we ever held the lock + max - longest time we ever held the lock + total - total time this lock was held + +From these number various other statistics can be derived, such as: + + hold time average = hold time total / acquisitions + +These numbers are gathered per lock class, per read/write state (when +applicable). + +It also tracks 4 contention points per class. A contention point is a call site +that had to wait on lock acquisition. + + - USAGE + +Look at the current lock statistics: + +( line numbers not part of actual output, done for clarity in the explanation + below ) + +# less /proc/lock_stat + +01 lock_stat version 0.2 +02 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- +03 class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total +04 ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- +05 +06 &inode->i_data.tree_lock-W: 15 21657 0.18 1093295.30 11547131054.85 58 10415 0.16 87.51 6387.60 +07 &inode->i_data.tree_lock-R: 0 0 0.00 0.00 0.00 23302 231198 0.25 8.45 98023.38 +08 -------------------------- +09 &inode->i_data.tree_lock 0 [<ffffffff8027c08f>] add_to_page_cache+0x5f/0x190 +10 +11 ............................................................................................................................................................................................... +12 +13 dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24 +14 ----------- +15 dcache_lock 180 [<ffffffff802c0d7e>] sys_getcwd+0x11e/0x230 +16 dcache_lock 165 [<ffffffff802c002a>] d_alloc+0x15a/0x210 +17 dcache_lock 33 [<ffffffff8035818d>] _atomic_dec_and_lock+0x4d/0x70 +18 dcache_lock 1 [<ffffffff802beef8>] shrink_dcache_parent+0x18/0x130 + +This excerpt shows the first two lock class statistics. Line 01 shows the +output version - each time the format changes this will be updated. Line 02-04 +show the header with column descriptions. Lines 05-10 and 13-18 show the actual +statistics. These statistics come in two parts; the actual stats separated by a +short separator (line 08, 14) from the contention points. + +The first lock (05-10) is a read/write lock, and shows two lines above the +short separator. The contention points don't match the column descriptors, +they have two: contentions and [<IP>] symbol. + + +View the top contending locks: + +# grep : /proc/lock_stat | head + &inode->i_data.tree_lock-W: 15 21657 0.18 1093295.30 11547131054.85 58 10415 0.16 87.51 6387.60 + &inode->i_data.tree_lock-R: 0 0 0.00 0.00 0.00 23302 231198 0.25 8.45 98023.38 + dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24 + &inode->i_mutex: 161 286 18446744073709 62882.54 1244614.55 3653 20598 18446744073709 62318.60 1693822.74 + &zone->lru_lock: 94 94 0.53 7.33 92.10 4366 32690 0.29 59.81 16350.06 + &inode->i_data.i_mmap_lock: 79 79 0.40 3.77 53.03 11779 87755 0.28 116.93 29898.44 + &q->__queue_lock: 48 50 0.52 31.62 86.31 774 13131 0.17 113.08 12277.52 + &rq->rq_lock_key: 43 47 0.74 68.50 170.63 3706 33929 0.22 107.99 17460.62 + &rq->rq_lock_key#2: 39 46 0.75 6.68 49.03 2979 32292 0.17 125.17 17137.63 + tasklist_lock-W: 15 15 1.45 10.87 32.70 1201 7390 0.58 62.55 13648.47 + +Clear the statistics: + +# echo 0 > /proc/lock_stat diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt index ef19142..10c8f69 100644 --- a/Documentation/sysrq.txt +++ b/Documentation/sysrq.txt @@ -43,7 +43,7 @@ On x86 - You press the key combo 'ALT-SysRq-<command key>'. Note - Some keyboards may not have a key labeled 'SysRq'. The 'SysRq' key is also known as the 'Print Screen' key. Also some keyboards cannot handle so many keys being pressed at the same time, so you might - have better luck with "press Alt", "press SysRq", "release Alt", + have better luck with "press Alt", "press SysRq", "release SysRq", "press <command key>", release everything. On SPARC - You press 'ALT-STOP-<command key>', I believe. |