Generic architecture support

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.

diff --git a/src/pcm/pcm_dmix.c b/src/pcm/pcm_dmix.c
index 06e82159e9fba8f3b60d58dddb41694f74e878c7..290459dd86042929d114de62a69a4a412d5e4a83 100644 (file)
--- a/src/pcm/pcm_dmix.c
+++ b/src/pcm/pcm_dmix.c
@@ -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;

diff --git a/src/pcm/pcm_dmix_generic.c b/src/pcm/pcm_dmix_generic.c
index 4ce7759879ca38313b860ecb743238bde8c6d0f0..dfd327fb5736ed417412567c6597c9f4de32b9e7 100644 (file)
--- a/src/pcm/pcm_dmix_generic.c
+++ b/src/pcm/pcm_dmix_generic.c
@@ -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;