[haiku-development] HDA
- From: Pete Goodeve <pete.goodeve@xxxxxxxxxxxx>
- To: Haiku Development <haiku-development@xxxxxxxxxxxxx>
- Date: Tue, 6 Nov 2012 16:35:27 -0800
Well, well, well... [and in fact, very well indeed! (:-)]
For months I've been trying to get a clue as to why all I got from my
ZaReason laptop audio was a sort of pulsing hash. Somehow I missed
ticket #8949 which reports exactly the same problem. I only discovered
it when a download of the latest alpha-4 nightly magically gave me
crystal clear sound! So many thanks, Axel!
I would love to have a brief explanation of the cause, though. I did note
that the Linux source code did have a quirk for my chipset that Haiku didn't
have, but I couldn't see how to connect it with the symptoms.
As the ticket notes, sound was obscured by this hash (actually pulsing
at the buffer exchange rate), but it could be cleared up -- sometimes
almost completely -- by violently moving a window around, or other display
activity. (I thought it might be processor loading, but found that maxing
out CPUs didn't help unless the display was changing.)
So can anyone suggest what the interaction was? I'd love to know,
and it would probably help my understanding of hardware considerably!
Dane, were your HDA problems like this?
There's just one glitch left for me... latency. Haiku HDA is using a couple
of 10240-sample buffers, which adds up to about 1/10 sec. Way too slow
for the real-time stuff I want to do. This puzzles me a bit, because Sean
reported a while back on how pleased he was by HDA's very low latency!
It's certain;y not inherent, because Ubuntu on the same laptop has
unnoticable latency when driven from USB-MIDI.
It's the next thing I have to look into, but auich on my previous machine
had a settings file where the buffers could be specified. Is there any
reason this wouldn't work for HDA too? (It might be preferable to have
this adjustable. There might be a trade-off between latency and
reliability on different machines.)
-- Pete --
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