4. PCI Resource Managements...............................................................................................................15
Full Code Example...........................................................................................................................15
Some Hafta’s ....................................................................................................................................17
Resource Allocation.........................................................................................................................18
Registration of Device Struct ...........................................................................................................21
PCI Entries .......................................................................................................................................21
5. PCM Interface......................................................................................................................................23
General .............................................................................................................................................23
Full Code Example...........................................................................................................................23
Constructor.......................................................................................................................................27
... And the Destructor? .....................................................................................................................29
Runtime Pointer - The Chest of PCM Information..........................................................................29
Hardware Description.............................................................................................................31
PCM Configurations...............................................................................................................33
DMA Buffer Information .......................................................................................................34
Running Status........................................................................................................................34
Private Data ............................................................................................................................34
Interrupt Callbacks .................................................................................................................35
Operators..........................................................................................................................................35
open callback ..........................................................................................................................35
close callback..........................................................................................................................36
ioctl callback...........................................................................................................................36
hw_params callback ...............................................................................................................36
hw_free callback.....................................................................................................................37
prepare callback......................................................................................................................37
trigger callback .......................................................................................................................38
pointer callback ......................................................................................................................38
copy and silence callbacks......................................................................................................39
ack callback ............................................................................................................................39
page callback ..........................................................................................................................39
Interrupt Handler..............................................................................................................................39
Interrupts at the period (fragment) boundary .........................................................................40
High-frequent timer interrupts................................................................................................40
On calling snd_pcm_period_elapsed() ..........................................................................41
Atomicity .........................................................................................................................................41
Constraints .......................................................................................................................................42
6. Control Interface .................................................................................................................................45
General .............................................................................................................................................45
Definition of Controls ......................................................................................................................45
Control Names ................................................................. ................................................................46
Global capture and playback ..................................................................................................46
Tone-controls ..........................................................................................................................46
3D controls .............................................................................................................................46
Mic boost ................................................................................................................................46
Access Flags.....................................................................................................................................47
Callbacks..........................................................................................................................................47
info callback ...........................................................................................................................47
iv
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