Hi,
On Sep 2 2017 10:19, Takashi Sakamoto wrote:
Well, in sound subsystem, there're a few drivers which uses hrtimer:
- snd-pcsp
- snd-sh-dac-audio
- snd-soc-imx-pcm-fiq
As a quick glance, 'snd-sh-dac-audio' includes the same bug, too. Additionally, 'snd-soc-imx-pcm-fiq' maintains hrtimer with loose manner in a point of state of PCM substream and it shall gain the same bug if improved. Later, I posted some patches for them.
After reading code thoroughly, I conclude that no need to fix these two drivers. They're programmed with own protections. The former (snd-sh-dac-audio) has 'struct snd_sh_dac.empty' and the latter (snd-soc-imx-pcm-fiq) has 'struct imx_pcm_runtime_data.playing' and '.capturing', to avoid cancellation of hrtimer on hrtimer callback.
These ways are not necessarily efficient but actually have no trouble. I leave them as is.
Regards
Takashi Sakamoto