ALSA: seq: Allow the modular sequencer registration
Many drivers bind the sequencer stuff in off-load by another driver
module, so that it's loaded only on demand. In the current code, this
mechanism doesn't work when the driver is built-in while the sequencer
is module. We check with IS_REACHABLE() and enable only when the
sequencer is in the same level of build.
However, this is basically a overshoot. The binder code
(snd-seq-device) is an individual module from the sequencer core
(snd-seq), and we just have to make the former a built-in while
keeping the latter a module for allowing the scenario like the above.
This patch achieves that by rewriting Kconfig slightly. Now, a driver
that provides the manual sequencer device binding should select
CONFIG_SND_SEQ_DEVICE in a way as
select SND_SEQ_DEVICE if SND_SEQUENCER != n
Note that the "!=n" is needed here to avoid the influence of the
sequencer core is module while the driver is built-in.
Also, since rawmidi.o may be linked with snd_seq_device.o when
built-in, we have to shuffle the code to make the linker happy.
(the kernel linker isn't smart enough yet to handle such a case.)
That is, snd_seq_device.c is moved to sound/core from sound/core/seq,
as well as Makefile.
Last but not least, the patch replaces the code using IS_REACHABLE()
with IS_ENABLED(), since now the condition meets always when enabled.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/drivers/Kconfig b/sound/drivers/Kconfig
index 0e3dc80..7144cc3 100644
--- a/sound/drivers/Kconfig
+++ b/sound/drivers/Kconfig
@@ -6,11 +6,13 @@
tristate
select SND_TIMER
select SND_HWDEP
+ select SND_SEQ_DEVICE if SND_SEQUENCER != n
config SND_OPL4_LIB
tristate
select SND_TIMER
select SND_HWDEP
+ select SND_SEQ_DEVICE if SND_SEQUENCER != n
# select SEQ stuff to min(SND_SEQUENCER,SND_XXX)
config SND_OPL3_LIB_SEQ