Davide Beatrici (@davidebeatrici) commented about dlls/wineoss.drv/oss.c:
+ WAVEFORMATEXTENSIBLE *fmtex = (WAVEFORMATEXTENSIBLE *)params->fmt; struct oss_stream *stream; oss_audioinfo ai; SIZE_T size;
+ /* We don't return early as priority is given to the other errors. */ + params->result = *params->stream ? AUDCLNT_E_ALREADY_INITIALIZED : S_OK; + + if (params->share == AUDCLNT_SHAREMODE_SHARED) { + params->period = def_period; + if (params->duration < 3 * params->period) + params->duration = 3 * params->period; + } else { + if (fmtex->Format.wFormatTag == WAVE_FORMAT_EXTENSIBLE && + (fmtex->dwChannelMask == 0 || fmtex->dwChannelMask & SPEAKER_RESERVED)) + params->result = AUDCLNT_E_UNSUPPORTED_FORMAT; Please note that this check was missing in the driver.
-- https://gitlab.winehq.org/wine/wine/-/merge_requests/2888#note_33629