Re: [alsa-devel] underruns and strange code in pcm_rate.c (and patch)

Hello.

Takashi Iwai wrote:

Not really. It checks appl_ptr of the client, not hw_ptr. appl_ptr is what app writes. So, as long as app writes only the period size, the hack isn't triggered.

No, its not that simple. When the partially filled period on slave appears, it then gets populated back. Namely, snd_pcm_write_areas() takes it via snd_pcm_avail_update(). It then adjusts the "frames" accordingly, and then also "size" gets infected. Then the hack triggers.