diff options
| author | Clemens Ladisch <clemens@ladisch.de> | 2005-10-19 14:38:30 +0200 |
|---|---|---|
| committer | Jaroslav Kysela <perex@suse.cz> | 2005-11-04 13:19:07 +0100 |
| commit | 87ef7779be825c187747b6b39a24d5326d610c53 (patch) | |
| tree | fd1ca6f88f1cadc68a07054beef067f210010039 /sound/core/seq | |
| parent | 051b51653309db976c9665f8d4b1774fa1f8124a (diff) | |
[ALSA] seq-timer: restrict timer frequencies
Modules: ALSA sequencer
When no default timer frequency has been set, initialize_timer() just
uses the maximum frequency supported by the timer, which is ridiculously
high on 96 kHz timers.
This patch introduces a default frequency of 1000 Hz for this case, and
makes sure that a frequency set by the user isn't too high.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Diffstat (limited to 'sound/core/seq')
| -rw-r--r-- | sound/core/seq/seq_timer.c | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/sound/core/seq/seq_timer.c b/sound/core/seq/seq_timer.c index 9c87d9f8ba9f..65b64a7c456d 100644 --- a/sound/core/seq/seq_timer.c +++ b/sound/core/seq/seq_timer.c @@ -34,6 +34,11 @@ extern int seq_default_timer_device; extern int seq_default_timer_subdevice; extern int seq_default_timer_resolution; +/* allowed sequencer timer frequencies, in Hz */ +#define MIN_FREQUENCY 10 +#define MAX_FREQUENCY 6250 +#define DEFAULT_FREQUENCY 1000 + #define SKEW_BASE 0x10000 /* 16bit shift */ static void snd_seq_timer_set_tick_resolution(seq_timer_tick_t *tick, @@ -325,17 +330,26 @@ int snd_seq_timer_stop(seq_timer_t * tmr) static int initialize_timer(seq_timer_t *tmr) { snd_timer_t *t; + unsigned long freq; + t = tmr->timeri->timer; snd_assert(t, return -EINVAL); + freq = tmr->preferred_resolution; + if (!freq) + freq = DEFAULT_FREQUENCY; + else if (freq < MIN_FREQUENCY) + freq = MIN_FREQUENCY; + else if (freq > MAX_FREQUENCY) + freq = MAX_FREQUENCY; + tmr->ticks = 1; - if (tmr->preferred_resolution && - ! (t->hw.flags & SNDRV_TIMER_HW_SLAVE)) { + if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) { unsigned long r = t->hw.resolution; if (! r && t->hw.c_resolution) r = t->hw.c_resolution(t); if (r) { - tmr->ticks = (unsigned int)(1000000000uL / (r * tmr->preferred_resolution)); + tmr->ticks = (unsigned int)(1000000000uL / (r * freq)); if (! tmr->ticks) tmr->ticks = 1; } |