=======================================================Documentation for the NeoMagic 256AV/256ZX sound driver=======================================================You're looking at version 1.1 of the driver.  (Woohoo!) It has beensuccessfully tested against the following laptop models:	Sony Z505S/Z505SX/Z505DX/Z505RX	Sony F150, F160, F180, F250, F270, F280, PCG-F26	Dell Latitude CPi, CPt (various submodels)There are a few caveats, which is why you should read the entirety ofthis document first.This driver was developed without any support or assistance fromNeoMagic.  There is no warranty, expressed, implied, or otherwise.  Itis free software in the public domain; feel free to use it, sell it,give it to your best friends, even claim that you wrote it (but why?!)but don't go whining to me, NeoMagic, Sony, Dell, or anyone elsewhen it blows up your computer.Version 1.1 contains a change to try and detect non-AC97 versions ofthe hardware, and not install itself appropriately.  It should alsoreinitialize the hardware on an APM resume event, assuming that APMwas configured into your kernel.============Installation============Enable the sound drivers, the OSS sound drivers, and then the NM256driver.  The NM256 driver *must* be configured as a module (it won'tgive you any other choice).Next, do the usual "make modules" and "make modules_install".Finally, insmod the soundcore, sound and nm256 modules.When the nm256 driver module is loaded, you should see a couple ofconfirmation messages in the kernel logfile indicating that it foundthe device (the device does *not* use any I/O ports or DMA channels).Now try playing a wav file, futz with the CD-ROM if you have one, etc.The NM256 is entirely a PCI-based device, and all the necessaryinformation is automatically obtained from the card.  It can only beconfigured as a module in a vain attempt to prevent people fromhurting themselves.  It works correctly if it shares an IRQ withanother device (it normally shares IRQ 9 with the builtin eepro100ethernet on the Sony Z505 laptops). It does not run the card in any sort of compatibility mode. It willnot work on laptops that have the SB16-compatible, AD1848-compatibleor CS4232-compatible codec/mixer; you will want to use the appropriatecompatible OSS driver with these chipsets.  I cannot provide anyassistance with machines using the SB16, AD1848 or CS4232 compatibleversions.  (The driver now attempts to detect the mixer version, andwill refuse to load if it believes the hardware is notAC97-compatible.)The sound support is very basic, but it does include simultaneousplayback and record capability.  The mixer support is also quitesimple, although this is in keeping with the rather limitedfunctionality of the chipset.There is no hardware synthesizer available, as the Losedows OPL-3 andMIDI support is done via hardware emulation.Only three recording devices are available on the Sony: themicrophone, the CD-ROM input, and the volume device (which correspondsto the stereo output).  (Other devices may be available on othermodels of laptops.)  The Z505 series does not have a builtin CD-ROM,so of course the CD-ROM input doesn't work.  It does work on laptopswith a builtin CD-ROM drive.The mixer device does not appear to have any tone controls, at leaston the Z505 series.  The mixer module checks for tone controls in theAC97 mixer, and will enable them if they are available.==============Known problems==============  * There are known problems with PCMCIA cards and the eepro100 ethernet     driver on the Z505S/Z505SX/Z505DX.  Keep reading.  * There are also potential problems with using a virtual X display, and    also problems loading the module after the X server has been started.     Keep reading.  * The volume control isn't anywhere near linear.  Sorry.  This will be    fixed eventually, when I get sufficiently annoyed with it.  (I doubt    it will ever be fixed now, since I've never gotten sufficiently    annoyed with it and nobody else seems to care.)  * There are reports that the CD-ROM volume is very low.  Since I do not    have a CD-ROM equipped laptop, I cannot test this (it's kinda hard to    do remotely).  * Only 8 fixed-rate speeds are supported.  This is mainly a chipset    limitation.  It may be possible to support other speeds in the future.  * There is no support for the telephone mixer/codec.  There is support    for a phonein/phoneout device in the mixer driver;  whether or not     it does anything is anyone's guess.  (Reports on this would be    appreciated.  You'll have to figure out how to get the phone to    go off-hook before it'll work, tho.)  * This driver was not written with any cooperation or support from    NeoMagic.  If you have any questions about this, see their website    for their official stance on supporting open source drivers.============Video memory============The NeoMagic sound engine uses a portion of the display memory to holdthe sound buffer.  (Crazy, eh?)  The NeoMagic video BIOS sets up aspecial pointer at the top of video RAM to indicate where the top ofthe audio buffer should be placed.At the present time XFree86 is apparently not aware of this.  It willthus write over either the pointer or the sound buffer with abandon.(Accelerated-X seems to do a better job here.)This implies a few things:  * Sometimes the NM256 driver has to guess at where the buffer     should be placed, especially if the module is loaded after the    X server is started.  It's usually correct, but it will consistently    fail on the Sony F250.  * Virtual screens greater than 1024x768x16 under XFree86 are    problematic on laptops with only 2.5MB of screen RAM. This    includes all of the 256AV-equipped laptops.  (Virtual displays    may or may not work on the 256ZX, which has at least 4MB of    video RAM.)If you start having problems with random noise being output eitherconstantly (this is the usual symptom on the F250), or when windowsare moved around (this is the usual symptom when using a virtualscreen), the best fix is to  * Don't use a virtual frame buffer.  * Make sure you load the NM256 module before the X server is    started.On the F250, it is possible to force the driver to load properly evenafter the XFree86 server is started by doing:	insmod nm256 buffertop=0x25a800This forces the audio buffers to the correct offset in screen RAM.One user has reported a similar problem on the Sony F270, althoughothers apparently aren't seeing any problems.  His suggested commandis	insmod nm256 buffertop=0x272800=================Official WWW site=================The official site for the NM256 driver is:	http://www.uglx.org/sony.htmlYou should always be able to get the latest version of the driver there,and the driver will be supported for the foreseeable future.==============Z505RX and IDE==============There appears to be a problem with the IDE chipset on the Z505RX; oneof the symptoms is that sound playback periodically hangs (when thedisk is accessed).  The user reporting the problem also reported thatenabling all of the IDE chipset workarounds in the kernel solved theproblem, tho obviously only one of them should be needed--if someonecan give me more details I would appreciate it.==============================Z505S/Z505SX on-board Ethernet==============================If you're using the on-board Ethernet Pro/100 ethernet support on the Z505series, I strongly encourage you to download the latest eepro100 driver fromDonald Becker's site:	ftp://cesdis.gsfc.nasa.gov/pub/linux/drivers/test/eepro100.cThere was a reported problem on the Z505SX that if the ethernetinterface is disabled and reenabled while the sound driver is loaded,the machine would lock up.  I have included a workaround that isworking satisfactorily.  However, you may occasionally see a messageabout "Releasing interrupts, over 1000 bad interrupts" which indicatesthat the workaround is doing its job.==================================PCMCIA and the Z505S/Z505SX/Z505DX==================================There is also a known problem with the Sony Z505S and Z505SX hangingif a PCMCIA card is inserted while the ethernet driver is loaded, orin some cases if the laptop is suspended.  This is caused by tons ofspurious IRQ 9s, probably generated from the PCMCIA or ACPI bridges.There is currently no fix for the problem that works in every case.The only known workarounds are to disable the ethernet interfacebefore inserting or removing a PCMCIA card, or with some cardsdisabling the PCMCIA card before ejecting it will also help theproblem with the laptop hanging when the card is ejected.One user has reported that setting the tcic's cs_irq to some valueother than 9 (like 11) fixed the problem.  This doesn't work on myZ505S, however--changing the value causes the cardmgr to stop seeingcard insertions and removals, cards don't seem to work correctly, andI still get hangs if a card is inserted when the kernel is booted.Using the latest ethernet driver and pcmcia package allows me toinsert an Adaptec 1480A SlimScsi card without the laptop hanging,although I still have to shut down the card before ejecting orpowering down the laptop.  However, similar experiments with a DE-660ethernet card still result in hangs when the card is inserted.  I ambeginning to think that the interrupts are CardBus-related, since theAdaptec card is a CardBus card, and the DE-660 is not; however, Idon't have any other CardBus cards to test with.======Thanks======First, I want to thank everyone (except NeoMagic of course) for theirgenerous support and encouragement.  I'd like to list everyone's namehere that replied during the development phase, but the list isamazingly long.I will be rather unfair and single out a few people, however:	Justin Maurer, for being the first random net.person to try it,	and for letting me login to his Z505SX to get it working there	Edi Weitz for trying out several different versions, and giving	me a lot of useful feedback	Greg Rumple for letting me login remotely to get the driver 	functional on the 256ZX, for his assistance on tracking	down all sorts of random stuff, and for trying out Accel-X	Zach Brown, for the initial AC97 mixer interface design	Jeff Garzik, for various helpful suggestions on the AC97	interface	"Mr. Bumpy" for feedback on the Z505RX	Bill Nottingham, for generous assistance in getting the mixer ID	code working=================Previous versions=================Versions prior to 0.3 (aka `noname') had problems with weird artifactsin the output and failed to set the recording rate properly.  Theseproblems have long since been fixed.Versions prior to 0.5 had problems with clicks in the output whenanything other than 16-bit stereo sound was being played, and also hadperiodic clicks when recording.Version 0.7 first incorporated support for the NM256ZX chipset, whichis found on some Dell Latitude laptops (the CPt, and apparentlysome CPi models as well).  It also included the generic AC97mixer module.Version 0.75 renamed all the functions and files with slightly moregeneric names.Note that previous versions of this document claimed that recording was8-bit only; it actually has been working for 16-bits all along.