Subject: Re: [linux-audio-dev] DRI + Jack conflict?
From: Paul Davis (paul_AT_linuxaudiosystems.com)
Date: Tue Feb 10 2004 - 02:32:35 EET
>On Mon, 2004-02-09 at 18:50, Dave Griffiths wrote:
>> jack works with intel830 DRI
>
>Hmm.. I only have Radeon's, so I'm a bit out of luck as far as testing
>other cards I guess.
>
>Anyone else have a positive/negative experience?
>
>(For clarification, it's only realtime jack (ie jackstart -R) that
>doesn't work).
its a basic problem with real time software, the POSIX API etc.
JACK tries to lock *all* the process memory. POSIX doesn't offer any
APIs that would allow us to lock only the parts we need locked without
a lot of impossibly ugly, non-portable kludgery. the part that needs
locking consists of any memory that will be touched by the code run in
the JACK-managed "audio" thread.
the implementation of DRI by certain video interface drivers means
that we end up trying to lock the video memory as well, and this tends
to fail for various reasons.
its not what to do about this. the most obvious answer is "don't try
to run real-time software on systems with these video drivers
installed". i know its not very satisfactory, but its all we have for
now.
--p
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