Re: Freeze Upon /dev/fd0 Use
Jeremy Katz (katzj@technojunkie.com)
Wed, 2 Sep 1998 13:46:10 -0600 (MDT)
On Wed, 2 Sep 1998, Rik van Riel wrote:
> > The good news is that ISA DMA is broken anyway, and it might just be an
> > acceptable option to not even have a "BROKEN_DMA" config option, but
> > just unconditionally refusing to allow two concurrent ISA DMA streams.
> > The only things I know of that do ISA DMA is the floppy and old sound
>
> There are also folks with good mainboards and Adaptec 1542
> controllers. Having sound skip on HD access is unacceptable
> if things worked great before the 'fix'...
>
> > cards, and if that means that the sound skips while accessing the floppy
> > I don't know if we really need to worry too much..
>
> Just making it a CONFIG option, or even a sysctl tunable
> option would make a good enough fix. On most systems it's
> not something to worry about anyway, since both floppy
> and sound are very much non-critical.
>
> Besides, we only need DMA to do floppy _writes_, reads can
> be done reliably without DMA (on a non-fifo fdc). That only
> results in some 32k+ interrupts/second from the fdc :)
This is all well and good; I admit that sound skipping while writing to
the floppy may not be the end of the world; but something DEFINITELY needs
to be done so that it doesn't lock the box. That would only lead to the
spread of FUD and more... unfortunately, due to school obligations, I'm
not going to get a chance to look at this more indepth until this weekend,
but when that time comes, I'll try and at least analyze the problem more
indepth.
But, there are a few things which still worry me. 1) It doesn't occur
every time. I can reliably reproduce it, but not every time I access the
fdd while sound is playing. 2) I was unable to do this under 2.0.35.
This may be due to 1 but could be indicative of something else.
But, like I said, I'll look into it more as I have time to.
Jeremy Katz
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