diff -Naur alsa-lib-1.0.10/configure alsa-lib-1.0.10-new/configure --- alsa-lib-1.0.10/configure 2005-11-16 14:44:47.000000000 +0000 +++ alsa-lib-1.0.10-new/configure 2008-02-23 18:36:50.000000000 +0000 @@ -18948,7 +18948,7 @@ esac cat >>confdefs.h <<_ACEOF -#define DATADIR "$dir" +#define DATADIR "/usr/share/" _ACEOF diff -Naur alsa-lib-1.0.10/src/pcm/pcm_dmix.c alsa-lib-1.0.10-new/src/pcm/pcm_dmix.c --- alsa-lib-1.0.10/src/pcm/pcm_dmix.c 2005-09-19 12:37:08.000000000 +0000 +++ alsa-lib-1.0.10-new/src/pcm/pcm_dmix.c 2008-02-23 18:38:16.000000000 +0000 @@ -50,6 +50,10 @@ const char *_snd_module_pcm_dmix = ""; #endif +#define CHUMBY_SECRET_SAUCE 1 +#define CHUMBY_RESYNC_DELAY 22 // ~.5ms at 44.1Khz + + #ifndef DOC_HIDDEN /* start is pending - this state happens when rate plugin does a delayed commit */ #define STATE_RUN_PENDING 1024 @@ -143,6 +147,8 @@ #include "pcm_dmix_i386.c" #elif defined(__x86_64__) #include "pcm_dmix_x86_64.c" +#elif defined(__arm__) +#include "pcm_dmix_arm.c" #else #include "pcm_dmix_generic.c" #endif @@ -260,12 +266,45 @@ */ slave_hw_ptr -= slave_hw_ptr % dmix->slave_period_size; slave_hw_ptr += dmix->slave_buffer_size; + + #ifdef CHUMBY_SECRET_SAUCE + if (dmix->slave_hw_ptr > dmix->slave_appl_ptr) { + // Either the slave_appl_ptr wrapped at dmix->slave_boundary + // or this is an underrun condition that has not been detected by the + // remainder of the system -- how can we tell? + // + // Well, slave_appl_ptr and slave_hw_ptr should never really be more + // than dmix->slave_buffer_size units apart (because valid pointers + // must reside within the boundaries of the ring buffer). So, if + // slave_appl_ptr has wrapped, slave_hw_ptr should be greater than + // slave_boundary because slave_buffer_size was added to it above and + // furthermore slave_appl_ptr should be less than slave_buffer_size. + // Otherwise, this is an underrun and slave_appl_ptr should be adjusted + // to slave_hw_ptr + CHUMBY_RESYNC_DELAY + + if (dmix->slave_appl_ptr <= dmix->slave_buffer_size && + slave_hw_ptr >= dmix->slave_boundary) { + // slave_appl_ptr wrapped at boundary + slave_hw_ptr -= dmix->slave_boundary; + } else { + // undetected underrun condition, adjust slave_appl_ptr + dmix->slave_appl_ptr = dmix->slave_hw_ptr + CHUMBY_RESYNC_DELAY; + } + } + + if (dmix->slave_appl_ptr < slave_hw_ptr) + slave_size = slave_hw_ptr - dmix->slave_appl_ptr; + else + slave_size = 0; + #else if (slave_hw_ptr >= dmix->slave_boundary) slave_hw_ptr -= dmix->slave_boundary; if (slave_hw_ptr < dmix->slave_appl_ptr) slave_size = slave_hw_ptr + (dmix->slave_boundary - dmix->slave_appl_ptr); else slave_size = slave_hw_ptr - dmix->slave_appl_ptr; + #endif + if (slave_size < size) size = slave_size; if (! size) @@ -463,6 +502,10 @@ dmix->hw_ptr %= pcm->period_size; dmix->appl_ptr = dmix->last_appl_ptr = dmix->hw_ptr; dmix->slave_appl_ptr = dmix->slave_hw_ptr = *dmix->spcm->hw.ptr; + + #ifdef CHUMBY_SECRET_SAUCE + dmix->slave_appl_ptr += CHUMBY_RESYNC_DELAY; + #endif return 0; } @@ -471,7 +514,17 @@ int err; snd_pcm_hwsync(dmix->spcm); - dmix->slave_appl_ptr = dmix->slave_hw_ptr = *dmix->spcm->hw.ptr; + dmix->slave_hw_ptr = *dmix->spcm->hw.ptr; + #ifndef CHUMBY_SECRET_SAUCE + dmix->slave_appl_ptr = dmix->slave_hw_ptr; + #else + { + snd_pcm_uframes_t delta = dmix->slave_appl_ptr - dmix->slave_hw_ptr; + if (delta > dmix->slave_buffer_size || delta < CHUMBY_RESYNC_DELAY) + dmix->slave_appl_ptr = dmix->slave_hw_ptr + CHUMBY_RESYNC_DELAY; + } + #endif + err = snd_timer_start(dmix->timer); if (err < 0) return err; diff -Naur alsa-lib-1.0.10/src/pcm/pcm_dmix_arm.c alsa-lib-1.0.10-new/src/pcm/pcm_dmix_arm.c --- alsa-lib-1.0.10/src/pcm/pcm_dmix_arm.c 1970-01-01 00:00:00.000000000 +0000 +++ alsa-lib-1.0.10-new/src/pcm/pcm_dmix_arm.c 2008-02-23 18:36:50.000000000 +0000 @@ -0,0 +1,22 @@ +/* + * optimized mixing code for i386 + */ + +#define MIX_AREAS1 mix_areas1 +#define MIX_AREAS1_MMX mix_areas1_mmx +#define MIX_AREAS2 mix_areas2 +#define LOCK_PREFIX "" +#include "pcm_dmix_arm.h" +#undef MIX_AREAS1 +#undef MIX_AREAS1_MMX +#undef MIX_AREAS2 +#undef LOCK_PREFIX + +static unsigned long long dmix_supported_format = + (1ULL << SND_PCM_FORMAT_S16_LE) | (1ULL << SND_PCM_FORMAT_S32_LE); + +static void mix_select_callbacks(snd_pcm_direct_t *dmix) +{ + dmix->u.dmix.mix_areas1 = mix_areas1; + dmix->u.dmix.mix_areas2 = mix_areas2; +} diff -Naur alsa-lib-1.0.10/src/pcm/pcm_dmix_arm.h alsa-lib-1.0.10-new/src/pcm/pcm_dmix_arm.h --- alsa-lib-1.0.10/src/pcm/pcm_dmix_arm.h 1970-01-01 00:00:00.000000000 +0000 +++ alsa-lib-1.0.10-new/src/pcm/pcm_dmix_arm.h 2008-02-23 18:36:50.000000000 +0000 @@ -0,0 +1,118 @@ +/** + * \file pcm/pcm_dmix_arm.h + * \ingroup PCM_Plugins + * \brief PCM Direct Stream Mixing (dmix) Plugin Interface - ARM assembler code + * \author Greg Hutchins + * \date 2007 + */ +/* + * PCM - Direct Stream Mixing + * Copyright (c) 2007 by Greg Hutchins + * + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as + * published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + */ + +/* + * for plain ARM + */ +static void MIX_AREAS1(unsigned int size, + volatile signed short *dst, signed short *src, + volatile signed int *sum, size_t dst_step, + size_t src_step, size_t sum_step) +{ + int _7fff = 0x7FFF; + + /* + * R0 - size + * R1 - dst + * R2 - src + * R3 - sum + */ + __asm__ ( + " ldr r9, %4\n" /* r9 = dst_step */ + " ldr r8, %5\n" /* r8 = src_step */ + " ldr r7, %6\n" /* r7 = sum_step */ + " ldr r6, %7\n" /* r6 = _7fff */ + "1:ldr lr, [%3]\n" /* old_sample = *sum */ + " ldrh ip, [%1]\n" /* ip = *dst */ + " cmp ip, #0\n" /* *dst == 0? */ + " ldrsh r4, [%2], +r8\n" /* sample = *src; src += src_step */ + " rsbeq r4, lr, r4\n" /* yes, sample -= *sum */ + " add lr, r4, lr\n" /* ARCH_ADD(sum, sample) */ + " str lr, [%3], +r7\n" /* *sum += sample; sum += sum_step */ + " mov r5, lr, asr #15\n" /* sample = saturate16(sample) */ + " teq r5, lr, asr #31\n" + " eorne lr, r6, lr, asr #31\n" + " subs %0, %0, #1\n" /* --size */ + " strh lr, [%1], +r9\n" /* *dst = sample; dst += dst_step */ + " bne 1b\n" /* if size != 0 branch 1b for more */ + + : /* no output regs */ + : "r" (size), "r" (dst), "r" (src), "r" (sum), + "m" (dst_step), "m" (src_step), "m" (sum_step), "m" (_7fff) + : "r4", "r5", "r6", "r7", "r8", "r9", "lr" + ); +} + + +/* + * for plain ARM, 32-bit version (24-bit resolution) + */ +static void MIX_AREAS2(unsigned int size, + volatile signed int *dst, signed int *src, + volatile signed int *sum, size_t dst_step, + size_t src_step, size_t sum_step) +{ + int _7fffff = 0x7FFFFF; + int _800000 = -0x800000; + + /* + * R0 - size + * R1 - dst + * R2 - src + * R3 - sum + */ + __asm__ ( + " ldr r9, %4\n" /* r9 = dst_step */ + " ldr r8, %5\n" /* r8 = src_step */ + " ldr r7, %6\n" /* r7 = sum_step */ + " ldr r6, %7\n" /* r6 = _7fffff */ + " ldr r5, %8\n" /* r5 = _800000 */ + "1:ldr lr, [%3]\n" /* old_sample = *sum */ + " ldr ip, [%1]\n" /* ip = *dst */ + " ldr r4, [%2], +r8\n" /* sample = *src; src += src_step */ + " mov r4, r4, asr #8\n" /* sample = *src / 256 */ + " cmp ip, #0\n" /* *dst == 0? */ + " rsbeq r4, lr, r4\n" /* yes, sample -= old_sample */ + " add lr, r4, lr\n" /* ARCH_ADD(sum, sample) */ + " str lr, [%3], +r7\n" /* *sum += sample; sum += sum_step */ + " cmp lr, r6\n" /* old_sample > 0x7fffff? */ + " movge lr, r6\n" /* yes, sample = 0x7fffff */ + " cmp lr, r5\n" /* old_sample < -0x800000? */ + " movlt lr, r5\n" /* yes, sample = -0x800000 */ + " subs %0, %0, #1\n" /* --size */ + " mov lr, lr, lsl #8\n" /* sample *= 256 */ + " str lr, [%1], +r9\n" /* *dst = sample; dst += dst_step */ + " bne 1b\n" /* if size != 0 branch 1b for more */ + + : /* no output regs */ + : "r" (size), "r" (dst), "r" (src), "r" (sum), + "m" (dst_step), "m" (src_step), "m" (sum_step), + "m" (_7fffff), "m" (_800000) + : "r4", "r5", "r6", "r7", "r8", "r9", "lr" + ); +}