[pulseaudio-discuss] Why tsched disabled when I use module-alsa-sink with 'mmap=0 tsched=1' parameters?

[김정연]

Dear developers,


I have question something about selecting logic between timer-based and IRQ
scheduling.

When I tried to load 'module-alsa-sink' with 'mmap=0 tsched=1' parameters,
tsched(timer-based scheduling) becomes disabled by below codes.

It seems tsched is allowed only mmap supported ALSA devices. Why tsched
disabled while use non-mmap driven ALSA?

So, I found able to use tsched with 'mmap=0' option with below workaround
code.

I think it seems possible to use 'mmap=0 tsched=1' together. There are any
reasons for that?


==========

diff -uNr ./a/alsa-sink.c ./b/alsa-sink.c

--- ./a/alsa-sink.c     2014-12-11 21:41:13.680373375 +0900

+++ ./b/alsa-sink.c     2014-12-11 21:45:50.032371336 +0900

@@ -2210,11 +2210,6 @@

         u->use_mmap = use_mmap = false;

     }


-    if (use_tsched && (!b || !d)) {

-        pa_log_info("Cannot enable timer-based scheduling, falling back to
sound IRQ scheduling.");

-        u->use_tsched = use_tsched = false;

-    }

-

     if (u->use_mmap)

         pa_log_info("Successfully enabled mmap() mode.");


diff -uNr ./a/alsa-util.c ./b/alsa-util.c

--- ./a/alsa-util.c     2014-12-11 21:41:13.680373375 +0900

+++ ./b/alsa-util.c     2014-12-11 21:46:46.228370922 +0900

@@ -240,9 +240,6 @@

         goto finish;

     }


-    if (!_use_mmap)

-        _use_tsched = false;

-

     if (!pa_alsa_pcm_is_hw(pcm_handle))

         _use_tsched = false;

==========


Thanks in advance,

KimJeongYeon
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