hi *!
while we were trying to debug the midi-related xruns in the current driver, i came across what looks like an unrelated locking bug to me:
static int snd_hdspm_midi_input_read (struct hdspm_midi *hmidi) ... spin_lock_irqsave (&hmidi->lock, flags); <--------------- n_pending = snd_hdspm_midi_input_available (hmidi->hdspm, hmidi->id); if (n_pending > 0) { if (hmidi->input) { if (n_pending > (int)sizeof (buf)) n_pending = sizeof (buf); for (i = 0; i < n_pending; ++i) buf[i] = snd_hdspm_midi_read_byte (hmidi->hdspm,
hmidi->id); if (n_pending) snd_rawmidi_receive (hmidi->input, buf, n_pending); } else { /* flush the MIDI input FIFO */ while (n_pending--) snd_hdspm_midi_read_byte (hmidi->hdspm, hmidi->id); } } hmidi->pending = 0;
hmidi->hdspm->control_register |= hmidi->ie;<------- !!! hdspm_write(hmidi->hdspm, HDSPM_controlRegister, hmidi->hdspm->control_register);
spin_unlock_irqrestore (&hmidi->lock, flags);<--------- return snd_hdspm_midi_output_write (hmidi); }
if i understand this whole business correctly, we should be holding the hdspm lock here, not the hmidi one.
please review the attached patch and apply if you think it's ok.
best,
jörn