[alsa-devel] alsa on Atmel at91

[Liam Girdwood]

On Thu, 2007-05-10 at 13:29 +0200, Michel Benoit wrote:
> I put this problem aside for a while but I have now managed to narrow
> it down a little
> 
> I'm trying to build alsa-lib 1.0.13 for a at91sam9260 target
> (arm926ej-s).  I'm using gcc 4.1.2 built with buildroot (uclibc).  I
> seem to be having a problem passing in arguments to some libasound
> functions.
> 

Iirc, the compiler bug also showed up on the dummy alsa device. Does the
same thing happen when playing to the ALSA dummy device on AT91 ?

> I have added some printfs to the following lib function (src/pcm.c):
> 
> 
> int snd_pcm_hw_params_get_period_size(const snd_pcm_hw_params_t
> *params, snd_pcm_uframes_t *val, int *dir)
> {
>        unsigned long _val;
> 
>        printf("get_period_size() %lu %lu %08x %08x %08x \n", _val,
> *val, val, dir, params );
> 
>        int err = snd_pcm_hw_param_get(params, SND_PCM_HW_PARAM_PERIOD_SIZE,
> &_val, NULL);
>        if (err >= 0)
>                *val = _val;
> 
>        printf("get_period_size() %lu %lu %08x %08x %08x %d\n", _val,
> *val, val, dir, params, err );
> 
>        return err;
> }
> 
> 
> as well as to the program that calls the lib function (test/pcm.c):
> 
> 
>        printf("period_size=%lu %08x dir=%d %08x params %08x \n",
> size, &size, dir, &dir, params);
>        err = snd_pcm_hw_params_get_period_size(params, &size, NULL);
>        if (err < 0) {
>                printf("Unable to get period size for playback: %s\n",
> snd_strerror(err));
>                return err;
>        }
>        period_size = size;
>        printf("period_size=%lu %08x dir=%d %08x params %08x \n",
> size, &size, dir, &dir, params);
> 
> 
> When I run the program I get the following output
> 
> # pcm
> Playback device is plughw:0,0

It's best to change this to hw:0,0 to help rule out any AT91 driver
issues. 

> Stream parameters are 44100Hz, S16_LE, 1 channels
> Sine wave rate is 440.0000Hz
> Using transfer method: write
> period_size=49572 bec48954 dir=0 bec48950 params bec489e4
> get_period_size() 1073758756 3200551252 bec48924 bec48954 bec489e4
> get_period_size() 1248 1248  bec48924 bec48954 bec489e4 0
> period_size=49572 bec48954 dir=0 bec48950 params bec489e4
> 
> which shows that the pointers to 'params' is ok but that the pointer
> to 'val' is incorrect (bec48924 instead of bec48954) and the pointer
> to 'dir' is also wrong (bec48954 instead of  bec48950 = the pointer to
> val).
> 
> What could be the cause of this kind of error?  Somehow the arguments
> passed to  snd_pcm_hw_params_get_period_size() are getting mangled.
> 
> I have tried removing all optimisations, using other versions of gcc
> (4.0.4 and 3.4.6) and using EABI instead of OABI.  I always get the
> same result.
> 
> Any tips on how I can proceed in debugging this problem?
> 
> Are there any compiler or linker flags that could be responsible ?
> 

Did you build any of the toolchains with OE ? I've not had any audio gcc
problems on ARM with OE toolchains since the cse bug.

Liam