If multiple instances of this driver are instantiated and try to send concurrently then the single static buffer snd_serial_generic_tx_work() will cause corruption in the data output. Move the buffer into the per-instance driver data to avoid this. Signed-off-by: John Keeping <jkeeping@inmusicbrands.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>