Prevent ALSA audio corruption

When using the ALSA driver, corruption would occur if `snd_pcm_writei`
was unable to consume the entire sound buffer. This would occur
frequently on the Raspberry Pi 3 which uses the `snd_bcm2835` audio
driver.

This bug resulted from incorrect pointer math on line 187, resulting in
the sample source pointer being advanced by `total * ad->channels` bytes
instead of `total * ad->channels` samples. In my opinion, the best fix
is to change `*src` to type `int16_t`, since that is the sample type in
use.

Fixes #43927.

(cherry picked from commit 25b2f82ccf)
This commit is contained in:
Cooper Harasyn 2020-11-27 16:05:59 -05:00 committed by Rémi Verschelde
parent d8c90f5f1e
commit 4bf141a47e
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@ -187,7 +187,7 @@ void AudioDriverALSA::thread_func(void *p_udata) {
int total = 0;
while (todo && !ad->exit_thread) {
uint8_t *src = (uint8_t *)ad->samples_out.ptr();
int16_t *src = (int16_t *)ad->samples_out.ptr();
int wrote = snd_pcm_writei(ad->pcm_handle, (void *)(src + (total * ad->channels)), todo);
if (wrote > 0) {