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Generic architecture support

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Support dmix on generic architectures without atomic operations but
using a semaphore to avoid concurrent accesses.  This is less effective
than atomic operations but should work on every system.
This commit is contained in:
Takashi Iwai 2005-03-29 14:13:04 +00:00
parent 6a6a70ffe7
commit 9207804912
2 changed files with 15 additions and 5 deletions
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9
src/pcm/pcm_dmix.c
View file

@ -228,8 +228,15 @@ static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm, snd_pcm_uframes_t size)
transfer = appl_ptr + size > pcm->buffer_size ? pcm->buffer_size - appl_ptr : size;
if (slave_appl_ptr + transfer > dmix->shmptr->s.buffer_size)
transfer = dmix->shmptr->s.buffer_size - slave_appl_ptr;
if (transfer)
if (transfer) {
#ifdef NO_CONCURRENT_ACCESS
snd_pcm_direct_semaphore_down(dmix, DIRECT_IPC_SEM_CLIENT);
#endif
mix_areas(dmix, src_areas, dst_areas, appl_ptr, slave_appl_ptr, transfer);
#ifdef NO_CONCURRENT_ACCESS
snd_pcm_direct_semaphore_up(dmix, DIRECT_IPC_SEM_CLIENT);
#endif
}
if (transfer >= size)
return;
size -= transfer;

11
src/pcm/pcm_dmix_generic.c
View file

@ -1,4 +1,5 @@
#if defined(__i386__) || defined(__x86_64__)
#if 0
//#if defined(__i386__) || defined(__x86_64__)
#define LOCK_PREFIX "lock ; "
#define ARCH_ADD(p,a) \
__asm__ __volatile__(LOCK_PREFIX "addl %1,%0" \
@ -36,12 +37,14 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
#define ARCH_CMPXCHG(ptr,o,n)\
((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
(unsigned long)(n),sizeof(*(ptr))))
#define IS_CONCURRENT 1 /* check race */
#endif
#ifndef ARCH_ADD
#warning Please, define atomic ADD and CMPXCHG for your architecture...
#define ARCH_ADD(p,a) (*(p) += (a))
#define ARCH_CMPXCHG(p,a,b) (*(p)) /* fake */
#define NO_CONCURRENT_ACCESS /* use semaphore to avoid race */
#define IS_CONCURRENT 0 /* no race check */
#endif
static void mix_areas1(unsigned int size,
@ -69,7 +72,7 @@ static void mix_areas1(unsigned int size,
else
sample = old_sample;
*dst = sample;
} while (*sum != old_sample);
} while (IS_CONCURRENT && *sum != old_sample);
if (!--size)
return;
src += src_step;
@ -103,7 +106,7 @@ static void mix_areas2(unsigned int size,
else
sample = old_sample * 256;
*dst = sample;
} while (*sum != old_sample);
} while (IS_CONCURRENT && *sum != old_sample);
if (!--size)
return;
src += src_step;