Hi, Tzung-Bi: On Wed, 2020-02-12 at 19:31 +0800, Tzung-Bi Shih wrote: > On Wed, Feb 12, 2020 at 4:19 PM CK Hu <ck.hu@xxxxxxxxxxxx> wrote: > > I think hdmi_conn_detect() and mtk_hdmi_audio_hook_plugged_cb() would be > > called in different thread. So it's necessary to use a mutex to protect > > this. > > Thanks for the reminder. I feel using mutex here is overkill. Please > see https://patchwork.kernel.org/patch/11378413/ for my proposed > solution. > I'm not only consider the race condition of plugged_cb and codec_dev. I also care about the atomic of mtk_cec_hpd_high() and hdmi->plugged_cb(). If these two function is not an atomic operation, below is an example of problem: <Status disconnected> 1. Thread A call mtk_hdmi_audio_hook_plugged_cb() 2. Thread A call mtk_cec_hpd_high() and get disconnected. <Status connected> 3. Thread B call hdmi_conn_detect() 4. Thread B call mtk_cec_hpd_high() and get connected 5. Thread B callback plugged_cb() with connected 6. Thread A callback plugged_cb() with disconnected (Bug here) Regards, CK > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-mediatek _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
