Messages in this thread | | | Date | Tue, 27 Oct 1998 11:24:52 +0100 | From | "Daniel J. Rodriksson" <> | Subject | Re: SB and 2.1.126 [NOT THE COMPILE PROBLEM] |
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Mike wrote: > > Having gently persuaded 2.1.126 to compile by applying: >
> > it all seemed fine. But sound is broken in quake (although everything > else seems to be happy). With quake, I just get white noise. Any ideas? > Yes I know why.
I have written the patch to have sb16 run full duplex but this means programming both the 8 and the 16 bit dma channels simultaneously.
Consequences: if we record at 16 bit we must do playback at 8 bit and viceversa.
Format conversions are handled transparently, so the process using the device should not worry.
For write_only or read_only processes, they can either allocate 16 or 8 bit.
This should be the quake case but quake is opening the device in read_write mode, so it gets 16 bit input and 8 bit playback. I said transparent !!! This is so unless you use the mmap technique ( quake uses it ), which implies that no software conversion can happen.
Hence these two possibilities exist: 1. We patch quake to have it open /dev/dsp read_only ( any volunteer ?? )
2. We all wait until Alan shows up ( anyone knows where is Alan ? ) and he decides whether he accepts the solution I have proposed to have full duplex keep working and quake too.
( The solution is to have the card be full duplex unless you start by writing data to the device * quake *. This means that for full duplex use you must always read first from the device. The SETTRIGER ioctl always tries to activate recording first if instructed to start both recording and playback so the approach should work fine )
Hope this makes the quake problem clear
Cheers
-- -------------------------------------------------------------| | Remember Scotch: 'THERE CAN BE ONLY ONE' | -------------------------------------------------------------| | Daniel J. Rodriksson | C-220,ETSI Telecomunicaciones | | djr@dit.upm.es | Avda Paraninfo S/N | | http://www.dit.upm.es/~djr | 28040 Madrid | | +34-1-3367366 + ext 469 | SPAIN | |------------------------------------------------------------|
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