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Fix handling of revents in snd_pcm_poll_descriptors_revents()

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The revents parameter is ambiguously defined whether it's a pointer
to a single event or an arary.

This patch defines the behavior of revents more strictly (in the
function description): it's a pointer of a single event.

Also fixed snd_pcm_wait_nocheck() to follow that rule.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2009-02-02 15:43:48 +01:00
parent 59ebaa8e9d
commit cb66600dd3
1 changed files with 19 additions and 23 deletions
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42
src/pcm/pcm.c
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@ -1430,7 +1430,7 @@ int snd_pcm_poll_descriptors(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int s
* \param pcm PCM handle * \param pcm PCM handle
* \param pfds array of poll descriptors * \param pfds array of poll descriptors
* \param nfds count of poll descriptors * \param nfds count of poll descriptors
* \param revents returned events * \param revents pointer to the returned (single) event
* \return zero if success, otherwise a negative error code * \return zero if success, otherwise a negative error code
* *
* This function does "demangling" of the revents mask returned from * This function does "demangling" of the revents mask returned from
@ -1440,6 +1440,9 @@ int snd_pcm_poll_descriptors(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int s
* syscall returned that some events are waiting, this function might * syscall returned that some events are waiting, this function might
* return empty set of events. In this case, application should * return empty set of events. In this case, application should
* do next event waiting using poll() or select(). * do next event waiting using poll() or select().
*
* Note: Even if multiple poll descriptors are used (i.e. pfds > 1),
* this function returns only a single event.
*/ */
int snd_pcm_poll_descriptors_revents(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int nfds, unsigned short *revents) int snd_pcm_poll_descriptors_revents(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int nfds, unsigned short *revents)
{ {
@ -2338,8 +2341,8 @@ int snd_pcm_wait(snd_pcm_t *pcm, int timeout)
int snd_pcm_wait_nocheck(snd_pcm_t *pcm, int timeout) int snd_pcm_wait_nocheck(snd_pcm_t *pcm, int timeout)
{ {
struct pollfd *pfd; struct pollfd *pfd;
unsigned short *revents; unsigned short revents = 0;
int i, npfds, pollio, err, err_poll; int npfds, err, err_poll;
npfds = snd_pcm_poll_descriptors_count(pcm); npfds = snd_pcm_poll_descriptors_count(pcm);
if (npfds <= 0 || npfds >= 16) { if (npfds <= 0 || npfds >= 16) {
@ -2347,7 +2350,6 @@ int snd_pcm_wait_nocheck(snd_pcm_t *pcm, int timeout)
return -EIO; return -EIO;
} }
pfd = alloca(sizeof(*pfd) * npfds); pfd = alloca(sizeof(*pfd) * npfds);
revents = alloca(sizeof(*revents) * npfds);
err = snd_pcm_poll_descriptors(pcm, pfd, npfds); err = snd_pcm_poll_descriptors(pcm, pfd, npfds);
if (err < 0) if (err < 0)
return err; return err;
@ -2356,7 +2358,6 @@ int snd_pcm_wait_nocheck(snd_pcm_t *pcm, int timeout)
return -EIO; return -EIO;
} }
do { do {
pollio = 0;
err_poll = poll(pfd, npfds, timeout); err_poll = poll(pfd, npfds, timeout);
if (err_poll < 0) { if (err_poll < 0) {
if (errno == EINTR) if (errno == EINTR)
@ -2365,28 +2366,23 @@ int snd_pcm_wait_nocheck(snd_pcm_t *pcm, int timeout)
} }
if (! err_poll) if (! err_poll)
break; break;
err = snd_pcm_poll_descriptors_revents(pcm, pfd, npfds, revents); err = snd_pcm_poll_descriptors_revents(pcm, pfd, npfds, &revents);
if (err < 0) if (err < 0)
return err; return err;
for (i = 0; i < npfds; i++) { if (revents & (POLLERR | POLLNVAL)) {
if (revents[i] & (POLLERR | POLLNVAL)) { /* check more precisely */
/* check more precisely */ switch (snd_pcm_state(pcm)) {
switch (snd_pcm_state(pcm)) { case SND_PCM_STATE_XRUN:
case SND_PCM_STATE_XRUN: return -EPIPE;
return -EPIPE; case SND_PCM_STATE_SUSPENDED:
case SND_PCM_STATE_SUSPENDED: return -ESTRPIPE;
return -ESTRPIPE; case SND_PCM_STATE_DISCONNECTED:
case SND_PCM_STATE_DISCONNECTED: return -ENODEV;
return -ENODEV; default:
default: return -EIO;
return -EIO;
}
} }
if ((revents[i] & (POLLIN | POLLOUT)) == 0)
continue;
pollio++;
} }
} while (! pollio); } while (!(revents & (POLLIN | POLLOUT)));
#if 0 /* very useful code to test poll related problems */ #if 0 /* very useful code to test poll related problems */
{ {
snd_pcm_sframes_t avail_update; snd_pcm_sframes_t avail_update;