Meaning of "pointer" operations

Meaning of "pointer" operations

[Kasparek Tomas]

Hi all,

I would like to ask you , ALSA gurus for some help.

What is exact meaning if "pointer" operations.

I know, that it should return offset in DMA buffer. What I'm not sure
about is unit - should the offset be in frames or in bytes. And should
it be offset against begin of DMA buffer (runtime->dma_addr) or
against actual period begin?

I'm writing ALSA driver for UDA1341 on Compaq iPAQ (H3600). It produce
some sound yet, but it's far from beeing usable. Actually I'm forking on
DMA part, and I got these messages from ALSA core (included in my debug
listing). If you could give me some hint, what this should be about, I
will be pleased :) (listing is a bit longer :(

command:

aplay -traw -c2 -r8000 -fS16_LE /usr/local/tmp/test3.raw

dmesg:

...
playback trigger
pcm_trigger id: 0 cmd: 1
  rate: 8000
  channels: 2
  period_size 1000
  periods: 4
  buffer_size: 4000
  dma_addr c1164000
  dma_bytes: 16000
  dma_area: 51 00 13 01 25 00 e2 00 a9 ff 65 00
process_dma
  sending period 4 (buffer_size: 4000)
    dma_bytes: 16000
    offset: 0
    dma_size: 4000
    data: 51 00 13 01 25 00 e2 00 a9 ff 65 00
OK
  sending period 3 (buffer_size: 4000)
    dma_bytes: 16000
    offset: 4000
    dma_size: 4000
    data: 44 ff 01 00 21 ff de ff 08 ff cb ff
OK
  sending period 2 (buffer_size: 4000)
    dma_bytes: 16000
    offset: 8000
    dma_size: 4000
    data: 69 31 83 32 88 33 a9 34 81 29 8d 2a
pcm trigger done
playback pointer
get_dma_pos 1320 -> 1320 -> 1320 -> 330
  min_align: 1
  hw_ptr_base: 00000000
  hw_ptr_interrupt: 00000000
  period_size: 1000
  updated pos: 330
dma_call_back
  -> period done (still pending 1) <-
playback pointer
get_dma_pos 4256 -> 256 -> 256 -> 64
  min_align: 1
  hw_ptr_base: 00000000
  hw_ptr_interrupt: 00000000
  period_size: 1000
  updated pos: 64
ALSA ../alsa-kernel/core/pcm_lib.c:120: U1nexpected hw_pointer value
(stream = 0, delta: -936, max jitter = 2000): wrong interrupt acknowledge?
process_dma
  sending period 2 (buffer_size: 4000)
    dma_bytes: 16000
    offset: 8000
    dma_size: 4000
    data: 69 31 83 32 88 33 a9 34 81 29 8d 2a
OK
  sending period 1 (buffer_size: 4000)
    dma_bytes: 16000
    offset: 12000
    dma_size: 4000
    data: 06 00 c3 00 4a fb fa fb 01 fa b5 fa
dma_callback done
dma_call_back
  -> period done (still pending 1) <-
playback pointer
get_dma_pos 8296 -> 296 -> 296 -> 74
  min_align: 1
  hw_ptr_base: 00000000
  hw_ptr_interrupt: 00000000
  period_size: 1000
  updated pos: 74
ALSA ../alsa-kernel/core/pcm_lib.c:120: U1nexpected hw_pointer value
(stream = 0, delta: -926, max jitter = 2000): wrong interrupt acknowledge?

Thanks

--

	Tomas Kasparek (sioux, xkaspa06)
 	 Tomas.Kasparek@[seznam.cz,volny.cz]
	 Linux@dcse.fee.vutbr.cz
	student UIVT FEI VUT Brno


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Re: Meaning of "pointer" operations

[Takashi Iwai]

Hi,

At Fri, 22 Mar 2002 11:09:20 +0100 (CET),
Kasparek Tomas wrote:
> 
> Hi all,
> 
> I would like to ask you , ALSA gurus for some help.
> 
> What is exact meaning if "pointer" operations.
> 
> I know, that it should return offset in DMA buffer. What I'm not sure
> about is unit - should the offset be in frames or in bytes. And should
> it be offset against begin of DMA buffer (runtime->dma_addr) or
> against actual period begin?

- in frames
- position from the DMA buffer start (not period boundary).

 
> I'm writing ALSA driver for UDA1341 on Compaq iPAQ (H3600). It produce
> some sound yet, but it's far from beeing usable. Actually I'm forking on
> DMA part, and I got these messages from ALSA core (included in my debug
> listing). If you could give me some hint, what this should be about, I
> will be pleased :) (listing is a bit longer :(
 
could you put the source somewhere on net?


ciao,

Takashi

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pmac.c compilation error

[matt yee-king]

Hello

I have tried to build alsa-driver 0.9beta12 on 

1. a rev A powerbook g4 400 (kernel 2.4.19-pre3-ben0 and 2.4.10-12a
system yellow dog 2.1)
2. a firewire imac g3 400 (kernel 2.4.10-12a yellow dog 2.1)

on both machines, i pass these arguments to configure:

./configure --with-cards=powermac --with-oss=yes --with-isapnp=no


configure outputs this:

___________

./configure --with-cards=powermac --wi
th-oss=yes --with-isapnp=no

loading cache ./config.cache
checking for gcc... (cached) gcc
checking whether the C compiler (gcc  ) works... yes
checking whether the C compiler (gcc  ) is a cross-compiler... no
checking whether we are using GNU C... (cached) yes
checking whether gcc accepts -g... (cached) yes
checking for ranlib... (cached) ranlib
checking for a BSD compatible install... (cached) /usr/bin/install -c
checking how to run the C preprocessor... (cached) gcc -E
checking for ANSI C header files... (cached) yes
checking for working const... (cached) yes
checking for inline... (cached) inline
checking whether time.h and sys/time.h may both be included... (cached)
yes
checking whether gcc needs -traditional... (cached) no
checking for current directory...
/usr/src/audio/alsa/alsa-driver-0.9.0beta12
checking for directory with kernel source...
/lib/modules/2.4.10-12a/build
checking for kernel version... 2.4.10-12a
checking for kernel linux/pm.h... yes
checking for kernel module symbol versions... yes
checking for PCI support in kernel... yes
checking for SGI/MIPS (HAL2) architecture... no
checking for directory to store kernel modules...
/lib/modules/2.4.10-12a/kernel
/sound
checking for verbose printk... on
checking for debug level... none
checking for processor type... ppc
checking for SMP... no
checking for ISA PnP driver in kernel... yes
checking for ISA PnP support... no
checking for driver version... 0.9.0beta12
checking for sequencer support... yes
checking for OSS/Free emulation... yes
checking for RTC callback support in kernel... no
checking for which soundcards to compile driver for... powermac
creating ./config.status
creating version
creating Makefile.conf
creating snddevices
creating utils/alsa-driver.spec
creating utils/buildrpm
creating toplevel.config
creating include/config.h
creating include/config1.h
include/config1.h is unchanged
creating include/version.h
include/version.h is unchanged

_____________


make barfs like this:

___________


gcc -DALSA_BUILD -D__KERNEL__ -DMODULE=1
-I/lib/modules/2.4.10-12a/build/include
-I/usr/src/audio/alsa/alsa-driver-0.9.0beta12/include -O2 -D__powerpc__
-fsigned-char -fno-builtin -msoft-float -ffixed-r2 -Wno-uninitialized
-mmultiple -mstring -DLINUX -Wall -Wstrict-prototypes
-fomit-frame-pointer -pipe   -c -o powermac.o powermac.c
../alsa-kernel/ppc/powermac.c:40: warning: `snd_enable' defined but not
used
gcc -DALSA_BUILD -D__KERNEL__ -DMODULE=1
-I/lib/modules/2.4.10-12a/build/include
-I/usr/src/audio/alsa/alsa-driver-0.9.0beta12/include -O2 -D__powerpc__
-fsigned-char -fno-builtin -msoft-float -ffixed-r2 -Wno-uninitialized
-mmultiple -mstring -DLINUX -Wall -Wstrict-prototypes
-fomit-frame-pointer -pipe   -c -o pmac.o pmac.c
In file included from pmac.c:1:
../alsa-kernel/ppc/pmac.c: In function `snd_pmac_suspend':
../alsa-kernel/ppc/pmac.c:1313: too many arguments to function
`snd_power_lock'
../alsa-kernel/ppc/pmac.c:1324: warning: implicit declaration of
function `disable_irq_R3ce4ca6f'
../alsa-kernel/ppc/pmac.c: In function `snd_pmac_resume':
../alsa-kernel/ppc/pmac.c:1337: too many arguments to function
`snd_power_lock'
../alsa-kernel/ppc/pmac.c:1353: warning: implicit declaration of
function `enable_irq_Rfcec0987'
make[1]: *** [pmac.o] Error 1
make[1]: Leaving directory
`/usr/src/audio/alsa/alsa-driver-0.9.0beta12/ppc'
make: *** [compile] Error 1

_______________


given that i am not a c coder, is there anything i can do to help get
this working?

cheers

matthew