1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
138 lines
5.6 KiB
Text
138 lines
5.6 KiB
Text
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Documentation for the Cirrus Logic/Crystal SoundFusion cs46xx/cs4280 audio
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controller chips (2001/05/11)
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The cs46xx audio driver supports the DSP line of Cirrus controllers.
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Specifically, the cs4610, cs4612, cs4614, cs4622, cs4624, cs4630 and the cs4280
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products. This driver uses the generic ac97_codec driver for AC97 codec
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support.
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Features:
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Full Duplex Playback/Capture supported from 8k-48k.
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16Bit Signed LE & 8Bit Unsigned, with Mono or Stereo supported.
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APM/PM - 2.2.x PM is enabled and functional. APM can also
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be enabled for 2.4.x by modifying the CS46XX_ACPI_SUPPORT macro
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definition.
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DMA playback buffer size is configurable from 16k (defaultorder=2) up to 2Meg
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(defaultorder=11). DMA capture buffer size is fixed at a single 4k page as
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two 2k fragments.
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MMAP seems to work well with QuakeIII, and test XMMS plugin.
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Myth2 works, but the polling logic is not fully correct, but is functional.
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The 2.4.4-ac6 gameport code in the cs461x joystick driver has been tested
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with a Microsoft Sidewinder joystick (cs461x.o and sidewinder.o). This
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audio driver must be loaded prior to the joystick driver to enable the
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DSP task image supporting the joystick device.
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Limitations:
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SPDIF is currently not supported.
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Primary codec support only. No secondary codec support is implemented.
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NOTES:
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Hercules Game Theatre XP - the EGPIO2 pin controls the external Amp,
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and has been tested.
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Module parameter hercules_egpio_disable set to 1, will force a 0 to EGPIODR
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to disable the external amplifier.
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VTB Santa Cruz - the GPIO7/GPIO8 on the Secondary Codec control
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the external amplifier for the "back" speakers, since we do not
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support the secondary codec then this external amp is not
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turned on. The primary codec external amplifier is supported but
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note that the AC97 EAPD bit is inverted logic (amp_voyetra()).
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DMA buffer size - there are issues with many of the Linux applications
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concerning the optimal buffer size. Several applications request a
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certain fragment size and number and then do not verify that the driver
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has the ability to support the requested configuration.
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SNDCTL_DSP_SETFRAGMENT ioctl is used to request a fragment size and
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number of fragments. Some applications exit if an error is returned
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on this particular ioctl. Therefore, in alignment with the other OSS audio
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drivers, no error is returned when a SETFRAGs IOCTL is received, but the
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values passed from the app are not used in any buffer calculation
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(ossfragshift/ossmaxfrags are not used).
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Use the "defaultorder=N" module parameter to change the buffer size if
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you have an application that requires a specific number of fragments
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or a specific buffer size (see below).
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Debug Interface
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---------------
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There is an ioctl debug interface to allow runtime modification of the
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debug print levels. This debug interface code can be disabled from the
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compilation process with commenting the following define:
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#define CSDEBUG_INTERFACE 1
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There is also a debug print methodolgy to select printf statements from
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different areas of the driver. A debug print level is also used to allow
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additional printfs to be active. Comment out the following line in the
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driver to disable compilation of the CS_DBGOUT print statements:
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#define CSDEBUG 1
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Please see the definitions for cs_debuglevel and cs_debugmask for additional
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information on the debug levels and sections.
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There is also a csdbg executable to allow runtime manipulation of these
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parameters. for a copy email: twoller@crystal.cirrus.com
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MODULE_PARMS definitions
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------------------------
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MODULE_PARM(defaultorder, "i");
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defaultorder=N
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where N is a value from 1 to 12
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The buffer order determines the size of the dma buffer for the driver.
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under Linux, a smaller buffer allows more responsiveness from many of the
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applications (e.g. games). A larger buffer allows some of the apps (esound)
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to not underrun the dma buffer as easily. As default, use 32k (order=3)
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rather than 64k as some of the games work more responsively.
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(2^N) * PAGE_SIZE = allocated buffer size
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MODULE_PARM(cs_debuglevel, "i");
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MODULE_PARM(cs_debugmask, "i");
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cs_debuglevel=N
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cs_debugmask=0xMMMMMMMM
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where N is a value from 0 (no debug printfs), to 9 (maximum)
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0xMMMMMMMM is a debug mask corresponding to the CS_xxx bits (see driver source).
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MODULE_PARM(hercules_egpio_disable, "i");
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hercules_egpio_disable=N
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where N is a 0 (enable egpio), or a 1 (disable egpio support)
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MODULE_PARM(initdelay, "i");
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initdelay=N
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This value is used to determine the millescond delay during the initialization
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code prior to powering up the PLL. On laptops this value can be used to
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assist with errors on resume, mostly with IBM laptops. Basically, if the
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system is booted under battery power then the mdelay()/udelay() functions fail to
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properly delay the required time. Also, if the system is booted under AC power
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and then the power removed, the mdelay()/udelay() functions will not delay properly.
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MODULE_PARM(powerdown, "i");
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powerdown=N
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where N is 0 (disable any powerdown of the internal blocks) or 1 (enable powerdown)
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MODULE_PARM(external_amp, "i");
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external_amp=1
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if N is set to 1, then force enabling the EAPD support in the primary AC97 codec.
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override the detection logic and force the external amp bit in the AC97 0x26 register
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to be reset (0). EAPD should be 0 for powerup, and 1 for powerdown. The VTB Santa Cruz
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card has inverted logic, so there is a special function for these cards.
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MODULE_PARM(thinkpad, "i");
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thinkpad=1
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if N is set to 1, then force enabling the clkrun functionality.
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Currently, when the part is being used, then clkrun is disabled for the entire system,
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but re-enabled when the driver is released or there is no outstanding open count.
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