linux/sound
Takashi Sakamoto 407359d44e ALSA: firewire-motu: export meter information to userspace as float value
In command DSP models, one meter information consists of 4 bytes for
IEEE 764 floating point (binary32). In previous patch, it is exported
to userspace as 32 bit storage since the storage is also handled in
ALSA firewire-motu driver as well in kernel space in which floating point
arithmetic is not preferable. On the other hand, ALSA firewire-motu driver
doesn't perform floating point calculation. The driver just gather meter
information from isochronous packets and fill structure fields for
userspace.

In 'header' target of Kbuild, UAPI headers are processed before installed.
In this timing, #ifdef macro with __KERNEL__ is removed. This mechanism
is useful in the case so that the 32 bit storage can be accessible as u32
type in kernel space and float type in user space. We can see the same
usage in ''struct acct_v3' in 'include/uapi/linux/acct.h'.

This commit is for the above idea. Additionally, due to message
protocol, meter information is filled with 0xffffffff in the end of
period but 0xffffffff is invalid as binary32. To avoid confusion in
userspace application, the last two elements are left without any
assignment.

Suggested-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20211027125529.54295-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2021-10-28 09:10:41 +02:00
..
ac97 bus: Make remove callback return void 2021-07-21 11:53:42 +02:00
aoa Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
arm ALSA: pxa2xx: Use managed PCM buffer allocation 2021-08-04 08:08:21 +02:00
atmel
core ALSA: memalloc: Fix a typo in snd_dma_buffer_sync() description 2021-10-19 08:07:41 +02:00
drivers ALSA: pcsp: Make hrtimer forwarding more robust 2021-09-28 10:58:08 +02:00
firewire ALSA: firewire-motu: export meter information to userspace as float value 2021-10-28 09:10:41 +02:00
hda Merge branch 'for-linus' into for-next 2021-10-14 15:54:30 +02:00
i2c ALSA: i2c: tea6330t: Remove redundant initialization of variable err 2021-06-12 09:32:14 +02:00
isa ALSA: gus: fix null pointer dereference on pointer block 2021-10-26 08:02:16 +02:00
mips ALSA: n64: check return value after calling platform_get_resource() 2021-06-12 09:31:13 +02:00
oss sound/oss/dmasound: Remove superfluous "break" 2021-05-27 08:24:23 +02:00
parisc parisc architecture updates for kernel 5.15: 2021-09-02 13:16:00 -07:00
pci ALSA: hda/realtek: Add a quirk for HP OMEN 15 mute LED 2021-10-28 09:09:57 +02:00
pcmcia ALSA: vx: Manage vx_core object with devres 2021-07-19 16:17:09 +02:00
ppc ALSA: ppc: fix error return code in snd_pmac_probe() 2021-06-16 08:52:29 +02:00
sh
soc Merge branch 'for-linus' into for-next 2021-10-14 15:54:30 +02:00
sparc ALSA: sparc: Fix assignment in if condition 2021-06-09 17:30:29 +02:00
spi
synth ALSA: emux: fix spelling mistakes 2021-07-05 19:34:22 +02:00
usb ALSA: ua101: fix division by zero at probe 2021-10-27 08:23:30 +02:00
virtio ALSA: virtio: Replace zero-length array with flexible-array member 2021-09-30 13:47:57 +02:00
x86 ALSA: memalloc: Correctly name as WC 2021-08-04 08:07:58 +02:00
xen
ac97_bus.c
Kconfig
last.c
Makefile
sound_core.c