On Friday 16 November 2001 12.06, you wrote: > > However, the hardware has no DMA, so the CPU needs to do the copying from > > the sound card memory to the host memory, which is done in the interrupt > > handler of the driver. This makes the card unsuitable for free-running > > memory-mapped mode, since the mapped host memory isn't updated until the > > interrupt is generated. This means that some programs using memory-mapped > > mode could get choppy sound using this driver. However, it could be fixed > > by a hack, which would not only copy in the interrupt handler, but also > > when the sample pointer is accessed, since one can assume that most > > free-running code will access the sample pointer before using the memory. > > I think it is quite an ugly hack, so I have not implemented it though. > > It's not an ugly hack. It's a working solution, because the pointer > routine is always called from interrupt and when the user space > code requests the actual position. It is not allowed to an application > to write data directly without knowledge of the actual position. We have > already this code in the CS46XX and EMU10K1 raw PCM drivers - see > snd_cs46xx_*_transfer routines. It is also guaranteed that the samples are > copied only once when needed.
Ok, I'll get right on it! Expect a patch within a few days. /Anders Torger _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
