![Takashi Iwai](/assets/img/avatar_default.png)
The recent rewrite of the sequencer time accounting using timespec64 in the commit [3915bf2946
: ALSA: seq_timer: use monotonic times internally] introduced a bad regression. Namely, the time reported back doesn't increase but goes back and forth. The culprit was obvious: the delta is stored to the result (cur_time = delta), instead of adding the delta (cur_time += delta)! Let's fix it. Fixes:3915bf2946
('ALSA: seq_timer: use monotonic times internally') Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=177571 Reported-by: Yves Guillemot <yc.guillemot@wanadoo.fr> Cc: <stable@vger.kernel.org> # v4.8+ Signed-off-by: Takashi Iwai <tiwai@suse.de>
496 lines
12 KiB
C
496 lines
12 KiB
C
/*
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* ALSA sequencer Timer
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* Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
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* Jaroslav Kysela <perex@perex.cz>
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <sound/core.h>
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#include <linux/slab.h>
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#include "seq_timer.h"
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#include "seq_queue.h"
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#include "seq_info.h"
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/* allowed sequencer timer frequencies, in Hz */
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#define MIN_FREQUENCY 10
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#define MAX_FREQUENCY 6250
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#define DEFAULT_FREQUENCY 1000
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#define SKEW_BASE 0x10000 /* 16bit shift */
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static void snd_seq_timer_set_tick_resolution(struct snd_seq_timer *tmr)
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{
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if (tmr->tempo < 1000000)
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tmr->tick.resolution = (tmr->tempo * 1000) / tmr->ppq;
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else {
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/* might overflow.. */
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unsigned int s;
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s = tmr->tempo % tmr->ppq;
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s = (s * 1000) / tmr->ppq;
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tmr->tick.resolution = (tmr->tempo / tmr->ppq) * 1000;
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tmr->tick.resolution += s;
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}
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if (tmr->tick.resolution <= 0)
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tmr->tick.resolution = 1;
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snd_seq_timer_update_tick(&tmr->tick, 0);
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}
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/* create new timer (constructor) */
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struct snd_seq_timer *snd_seq_timer_new(void)
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{
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struct snd_seq_timer *tmr;
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tmr = kzalloc(sizeof(*tmr), GFP_KERNEL);
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if (!tmr)
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return NULL;
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spin_lock_init(&tmr->lock);
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/* reset setup to defaults */
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snd_seq_timer_defaults(tmr);
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/* reset time */
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snd_seq_timer_reset(tmr);
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return tmr;
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}
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/* delete timer (destructor) */
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void snd_seq_timer_delete(struct snd_seq_timer **tmr)
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{
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struct snd_seq_timer *t = *tmr;
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*tmr = NULL;
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if (t == NULL) {
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pr_debug("ALSA: seq: snd_seq_timer_delete() called with NULL timer\n");
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return;
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}
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t->running = 0;
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/* reset time */
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snd_seq_timer_stop(t);
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snd_seq_timer_reset(t);
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kfree(t);
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}
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void snd_seq_timer_defaults(struct snd_seq_timer * tmr)
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{
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unsigned long flags;
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spin_lock_irqsave(&tmr->lock, flags);
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/* setup defaults */
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tmr->ppq = 96; /* 96 PPQ */
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tmr->tempo = 500000; /* 120 BPM */
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snd_seq_timer_set_tick_resolution(tmr);
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tmr->running = 0;
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tmr->type = SNDRV_SEQ_TIMER_ALSA;
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tmr->alsa_id.dev_class = seq_default_timer_class;
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tmr->alsa_id.dev_sclass = seq_default_timer_sclass;
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tmr->alsa_id.card = seq_default_timer_card;
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tmr->alsa_id.device = seq_default_timer_device;
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tmr->alsa_id.subdevice = seq_default_timer_subdevice;
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tmr->preferred_resolution = seq_default_timer_resolution;
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tmr->skew = tmr->skew_base = SKEW_BASE;
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spin_unlock_irqrestore(&tmr->lock, flags);
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}
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static void seq_timer_reset(struct snd_seq_timer *tmr)
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{
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/* reset time & songposition */
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tmr->cur_time.tv_sec = 0;
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tmr->cur_time.tv_nsec = 0;
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tmr->tick.cur_tick = 0;
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tmr->tick.fraction = 0;
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}
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void snd_seq_timer_reset(struct snd_seq_timer *tmr)
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{
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unsigned long flags;
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spin_lock_irqsave(&tmr->lock, flags);
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seq_timer_reset(tmr);
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spin_unlock_irqrestore(&tmr->lock, flags);
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}
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/* called by timer interrupt routine. the period time since previous invocation is passed */
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static void snd_seq_timer_interrupt(struct snd_timer_instance *timeri,
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unsigned long resolution,
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unsigned long ticks)
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{
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unsigned long flags;
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struct snd_seq_queue *q = timeri->callback_data;
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struct snd_seq_timer *tmr;
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if (q == NULL)
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return;
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tmr = q->timer;
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if (tmr == NULL)
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return;
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spin_lock_irqsave(&tmr->lock, flags);
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if (!tmr->running) {
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spin_unlock_irqrestore(&tmr->lock, flags);
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return;
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}
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resolution *= ticks;
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if (tmr->skew != tmr->skew_base) {
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/* FIXME: assuming skew_base = 0x10000 */
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resolution = (resolution >> 16) * tmr->skew +
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(((resolution & 0xffff) * tmr->skew) >> 16);
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}
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/* update timer */
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snd_seq_inc_time_nsec(&tmr->cur_time, resolution);
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/* calculate current tick */
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snd_seq_timer_update_tick(&tmr->tick, resolution);
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/* register actual time of this timer update */
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ktime_get_ts64(&tmr->last_update);
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spin_unlock_irqrestore(&tmr->lock, flags);
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/* check queues and dispatch events */
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snd_seq_check_queue(q, 1, 0);
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}
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/* set current tempo */
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int snd_seq_timer_set_tempo(struct snd_seq_timer * tmr, int tempo)
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{
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unsigned long flags;
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if (snd_BUG_ON(!tmr))
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return -EINVAL;
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if (tempo <= 0)
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return -EINVAL;
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spin_lock_irqsave(&tmr->lock, flags);
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if ((unsigned int)tempo != tmr->tempo) {
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tmr->tempo = tempo;
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snd_seq_timer_set_tick_resolution(tmr);
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}
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spin_unlock_irqrestore(&tmr->lock, flags);
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return 0;
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}
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/* set current ppq */
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int snd_seq_timer_set_ppq(struct snd_seq_timer * tmr, int ppq)
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{
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unsigned long flags;
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if (snd_BUG_ON(!tmr))
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return -EINVAL;
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if (ppq <= 0)
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return -EINVAL;
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spin_lock_irqsave(&tmr->lock, flags);
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if (tmr->running && (ppq != tmr->ppq)) {
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/* refuse to change ppq on running timers */
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/* because it will upset the song position (ticks) */
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spin_unlock_irqrestore(&tmr->lock, flags);
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pr_debug("ALSA: seq: cannot change ppq of a running timer\n");
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return -EBUSY;
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}
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tmr->ppq = ppq;
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snd_seq_timer_set_tick_resolution(tmr);
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spin_unlock_irqrestore(&tmr->lock, flags);
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return 0;
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}
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/* set current tick position */
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int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr,
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snd_seq_tick_time_t position)
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{
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unsigned long flags;
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if (snd_BUG_ON(!tmr))
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return -EINVAL;
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spin_lock_irqsave(&tmr->lock, flags);
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tmr->tick.cur_tick = position;
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tmr->tick.fraction = 0;
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spin_unlock_irqrestore(&tmr->lock, flags);
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return 0;
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}
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/* set current real-time position */
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int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr,
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snd_seq_real_time_t position)
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{
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unsigned long flags;
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if (snd_BUG_ON(!tmr))
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return -EINVAL;
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snd_seq_sanity_real_time(&position);
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spin_lock_irqsave(&tmr->lock, flags);
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tmr->cur_time = position;
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spin_unlock_irqrestore(&tmr->lock, flags);
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return 0;
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}
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/* set timer skew */
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int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew,
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unsigned int base)
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{
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unsigned long flags;
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if (snd_BUG_ON(!tmr))
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return -EINVAL;
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/* FIXME */
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if (base != SKEW_BASE) {
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pr_debug("ALSA: seq: invalid skew base 0x%x\n", base);
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return -EINVAL;
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}
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spin_lock_irqsave(&tmr->lock, flags);
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tmr->skew = skew;
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spin_unlock_irqrestore(&tmr->lock, flags);
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return 0;
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}
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int snd_seq_timer_open(struct snd_seq_queue *q)
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{
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struct snd_timer_instance *t;
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struct snd_seq_timer *tmr;
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char str[32];
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int err;
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tmr = q->timer;
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if (snd_BUG_ON(!tmr))
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return -EINVAL;
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if (tmr->timeri)
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return -EBUSY;
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sprintf(str, "sequencer queue %i", q->queue);
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if (tmr->type != SNDRV_SEQ_TIMER_ALSA) /* standard ALSA timer */
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return -EINVAL;
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if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
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tmr->alsa_id.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
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err = snd_timer_open(&t, str, &tmr->alsa_id, q->queue);
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if (err < 0 && tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_SLAVE) {
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if (tmr->alsa_id.dev_class != SNDRV_TIMER_CLASS_GLOBAL ||
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tmr->alsa_id.device != SNDRV_TIMER_GLOBAL_SYSTEM) {
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struct snd_timer_id tid;
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memset(&tid, 0, sizeof(tid));
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tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
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tid.dev_sclass = SNDRV_TIMER_SCLASS_SEQUENCER;
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tid.card = -1;
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tid.device = SNDRV_TIMER_GLOBAL_SYSTEM;
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err = snd_timer_open(&t, str, &tid, q->queue);
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}
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}
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if (err < 0) {
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pr_err("ALSA: seq fatal error: cannot create timer (%i)\n", err);
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return err;
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}
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t->callback = snd_seq_timer_interrupt;
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t->callback_data = q;
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t->flags |= SNDRV_TIMER_IFLG_AUTO;
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spin_lock_irq(&tmr->lock);
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tmr->timeri = t;
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spin_unlock_irq(&tmr->lock);
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return 0;
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}
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int snd_seq_timer_close(struct snd_seq_queue *q)
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{
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struct snd_seq_timer *tmr;
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struct snd_timer_instance *t;
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tmr = q->timer;
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if (snd_BUG_ON(!tmr))
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return -EINVAL;
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spin_lock_irq(&tmr->lock);
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t = tmr->timeri;
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tmr->timeri = NULL;
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spin_unlock_irq(&tmr->lock);
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if (t)
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snd_timer_close(t);
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return 0;
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}
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static int seq_timer_stop(struct snd_seq_timer *tmr)
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{
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if (! tmr->timeri)
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return -EINVAL;
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if (!tmr->running)
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return 0;
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tmr->running = 0;
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snd_timer_pause(tmr->timeri);
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return 0;
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}
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int snd_seq_timer_stop(struct snd_seq_timer *tmr)
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{
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unsigned long flags;
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int err;
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spin_lock_irqsave(&tmr->lock, flags);
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err = seq_timer_stop(tmr);
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spin_unlock_irqrestore(&tmr->lock, flags);
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return err;
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}
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static int initialize_timer(struct snd_seq_timer *tmr)
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{
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struct snd_timer *t;
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unsigned long freq;
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t = tmr->timeri->timer;
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if (snd_BUG_ON(!t))
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return -EINVAL;
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freq = tmr->preferred_resolution;
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if (!freq)
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freq = DEFAULT_FREQUENCY;
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else if (freq < MIN_FREQUENCY)
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freq = MIN_FREQUENCY;
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else if (freq > MAX_FREQUENCY)
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freq = MAX_FREQUENCY;
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tmr->ticks = 1;
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if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
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unsigned long r = t->hw.resolution;
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if (! r && t->hw.c_resolution)
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r = t->hw.c_resolution(t);
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if (r) {
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tmr->ticks = (unsigned int)(1000000000uL / (r * freq));
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if (! tmr->ticks)
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tmr->ticks = 1;
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}
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}
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tmr->initialized = 1;
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return 0;
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}
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static int seq_timer_start(struct snd_seq_timer *tmr)
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{
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if (! tmr->timeri)
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return -EINVAL;
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if (tmr->running)
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seq_timer_stop(tmr);
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seq_timer_reset(tmr);
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if (initialize_timer(tmr) < 0)
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return -EINVAL;
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snd_timer_start(tmr->timeri, tmr->ticks);
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tmr->running = 1;
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ktime_get_ts64(&tmr->last_update);
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return 0;
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}
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int snd_seq_timer_start(struct snd_seq_timer *tmr)
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{
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unsigned long flags;
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int err;
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spin_lock_irqsave(&tmr->lock, flags);
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err = seq_timer_start(tmr);
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spin_unlock_irqrestore(&tmr->lock, flags);
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return err;
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}
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static int seq_timer_continue(struct snd_seq_timer *tmr)
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{
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if (! tmr->timeri)
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return -EINVAL;
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if (tmr->running)
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return -EBUSY;
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if (! tmr->initialized) {
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seq_timer_reset(tmr);
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if (initialize_timer(tmr) < 0)
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return -EINVAL;
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}
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snd_timer_start(tmr->timeri, tmr->ticks);
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tmr->running = 1;
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ktime_get_ts64(&tmr->last_update);
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return 0;
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}
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int snd_seq_timer_continue(struct snd_seq_timer *tmr)
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{
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unsigned long flags;
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int err;
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spin_lock_irqsave(&tmr->lock, flags);
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err = seq_timer_continue(tmr);
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spin_unlock_irqrestore(&tmr->lock, flags);
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return err;
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}
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/* return current 'real' time. use timeofday() to get better granularity. */
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snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr)
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{
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snd_seq_real_time_t cur_time;
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unsigned long flags;
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spin_lock_irqsave(&tmr->lock, flags);
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cur_time = tmr->cur_time;
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if (tmr->running) {
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struct timespec64 tm;
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ktime_get_ts64(&tm);
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tm = timespec64_sub(tm, tmr->last_update);
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cur_time.tv_nsec += tm.tv_nsec;
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cur_time.tv_sec += tm.tv_sec;
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snd_seq_sanity_real_time(&cur_time);
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}
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spin_unlock_irqrestore(&tmr->lock, flags);
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return cur_time;
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}
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/* TODO: use interpolation on tick queue (will only be useful for very
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high PPQ values) */
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snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr)
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{
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return tmr->tick.cur_tick;
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}
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#ifdef CONFIG_SND_PROC_FS
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/* exported to seq_info.c */
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void snd_seq_info_timer_read(struct snd_info_entry *entry,
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struct snd_info_buffer *buffer)
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{
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int idx;
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struct snd_seq_queue *q;
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struct snd_seq_timer *tmr;
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struct snd_timer_instance *ti;
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unsigned long resolution;
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for (idx = 0; idx < SNDRV_SEQ_MAX_QUEUES; idx++) {
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q = queueptr(idx);
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if (q == NULL)
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continue;
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if ((tmr = q->timer) == NULL ||
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(ti = tmr->timeri) == NULL) {
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queuefree(q);
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continue;
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}
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snd_iprintf(buffer, "Timer for queue %i : %s\n", q->queue, ti->timer->name);
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resolution = snd_timer_resolution(ti) * tmr->ticks;
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snd_iprintf(buffer, " Period time : %lu.%09lu\n", resolution / 1000000000, resolution % 1000000000);
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snd_iprintf(buffer, " Skew : %u / %u\n", tmr->skew, tmr->skew_base);
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queuefree(q);
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}
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}
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#endif /* CONFIG_SND_PROC_FS */
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