This patch fixes the issue where TTY-migrated synths would take a while to shut up after hitting numpad enter key. When calling synth_flush, even though XOFF character is sent as high priority, data buffered in TTY layer is still sent to the synth. This patch flushes that buffered data when synth_flush is called. It also tries to ensure that hardware flow control is enabled, by setting CRTSCTS using tty's termios. Reported-by: John Covici Signed-off-by: Okash Khawaja Reviewed-by: Samuel Thibault Index: linux-staging/drivers/staging/speakup/serialio.c =================================================================== --- linux-staging.orig/drivers/staging/speakup/serialio.c +++ linux-staging/drivers/staging/speakup/serialio.c @@ -30,6 +30,7 @@ static void spk_serial_tiocmset(unsigned int set, unsigned int clear); static unsigned char spk_serial_in(void); static unsigned char spk_serial_in_nowait(void); +static void spk_serial_flush_buffer(void); struct spk_io_ops spk_serial_io_ops = { .synth_out = spk_serial_out, @@ -37,6 +38,7 @@ .tiocmset = spk_serial_tiocmset, .synth_in = spk_serial_in, .synth_in_nowait = spk_serial_in_nowait, + .flush_buffer = spk_serial_flush_buffer, }; EXPORT_SYMBOL_GPL(spk_serial_io_ops); @@ -268,6 +270,11 @@ return inb_p(speakup_info.port_tts + UART_RX); } +static void spk_serial_flush_buffer(void) +{ + /* TODO: flush the UART 16550 buffer */ +} + static int spk_serial_out(struct spk_synth *in_synth, const char ch) { if (in_synth->alive && spk_wait_for_xmitr(in_synth)) { Index: linux-staging/drivers/staging/speakup/spk_ttyio.c =================================================================== --- linux-staging.orig/drivers/staging/speakup/spk_ttyio.c +++ linux-staging/drivers/staging/speakup/spk_ttyio.c @@ -85,6 +85,7 @@ static void spk_ttyio_tiocmset(unsigned int set, unsigned int clear); static unsigned char spk_ttyio_in(void); static unsigned char spk_ttyio_in_nowait(void); +static void spk_ttyio_flush_buffer(void); struct spk_io_ops spk_ttyio_ops = { .synth_out = spk_ttyio_out, @@ -92,13 +93,22 @@ .tiocmset = spk_ttyio_tiocmset, .synth_in = spk_ttyio_in, .synth_in_nowait = spk_ttyio_in_nowait, + .flush_buffer = spk_ttyio_flush_buffer, }; EXPORT_SYMBOL_GPL(spk_ttyio_ops); +static inline void get_termios(struct tty_struct *tty, struct ktermios *out_termios) +{ + down_read(&tty->termios_rwsem); + *out_termios = tty->termios; + up_read(&tty->termios_rwsem); +} + static int spk_ttyio_initialise_ldisc(int ser) { int ret = 0; struct tty_struct *tty; + struct ktermios tmp_termios; ret = tty_register_ldisc(N_SPEAKUP, &spk_ttyio_ldisc_ops); if (ret) { @@ -127,6 +137,20 @@ } clear_bit(TTY_HUPPED, &tty->flags); + /* ensure hardware flow control is enabled */ + get_termios(tty, &tmp_termios); + if (!(tmp_termios.c_cflag & CRTSCTS)) { + tmp_termios.c_cflag |= CRTSCTS; + tty_set_termios(tty, &tmp_termios); + /* + * check c_cflag to see if it's updated as tty_set_termios may not return + * error even when no tty bits are changed by the request. + */ + get_termios(tty, &tmp_termios); + if (!(tmp_termios.c_cflag & CRTSCTS)) + pr_warn("speakup: Failed to set hardware flow control\n"); + } + tty_unlock(tty); ret = tty_set_ldisc(tty, N_SPEAKUP); @@ -201,6 +225,11 @@ return (rv == 0xff) ? 0 : rv; } +static void spk_ttyio_flush_buffer(void) +{ + speakup_tty->ops->flush_buffer(speakup_tty); +} + int spk_ttyio_synth_probe(struct spk_synth *synth) { int rv = spk_ttyio_initialise_ldisc(synth->ser); Index: linux-staging/drivers/staging/speakup/spk_types.h =================================================================== --- linux-staging.orig/drivers/staging/speakup/spk_types.h +++ linux-staging/drivers/staging/speakup/spk_types.h @@ -154,6 +154,7 @@ void (*tiocmset)(unsigned int set, unsigned int clear); unsigned char (*synth_in)(void); unsigned char (*synth_in_nowait)(void); + void (*flush_buffer)(void); }; struct spk_synth { Index: linux-staging/drivers/staging/speakup/speakup_audptr.c =================================================================== --- linux-staging.orig/drivers/staging/speakup/speakup_audptr.c +++ linux-staging/drivers/staging/speakup/speakup_audptr.c @@ -127,6 +127,7 @@ static void synth_flush(struct spk_synth *synth) { + synth->io_ops->flush_buffer(); synth->io_ops->send_xchar(SYNTH_CLEAR); synth->io_ops->synth_out(synth, PROCSPEECH); } Index: linux-staging/drivers/staging/speakup/speakup_decext.c =================================================================== --- linux-staging.orig/drivers/staging/speakup/speakup_decext.c +++ linux-staging/drivers/staging/speakup/speakup_decext.c @@ -221,6 +221,7 @@ static void synth_flush(struct spk_synth *synth) { in_escape = 0; + synth->io_ops->flush_buffer(); synth->synth_immediate(synth, "\033P;10z\033\\"); } Index: linux-staging/drivers/staging/speakup/speakup_dectlk.c =================================================================== --- linux-staging.orig/drivers/staging/speakup/speakup_dectlk.c +++ linux-staging/drivers/staging/speakup/speakup_dectlk.c @@ -293,6 +293,7 @@ synth->io_ops->synth_out(synth, ']'); in_escape = 0; is_flushing = 1; + synth->io_ops->flush_buffer(); synth->io_ops->synth_out(synth, SYNTH_CLEAR); } Index: linux-staging/drivers/staging/speakup/speakup_spkout.c =================================================================== --- linux-staging.orig/drivers/staging/speakup/speakup_spkout.c +++ linux-staging/drivers/staging/speakup/speakup_spkout.c @@ -125,6 +125,7 @@ static void synth_flush(struct spk_synth *synth) { + synth->io_ops->flush_buffer(); synth->io_ops->send_xchar(SYNTH_CLEAR); } Index: linux-staging/drivers/staging/speakup/synth.c =================================================================== --- linux-staging.orig/drivers/staging/speakup/synth.c +++ linux-staging/drivers/staging/speakup/synth.c @@ -120,6 +120,7 @@ void spk_synth_flush(struct spk_synth *synth) { + synth->io_ops->flush_buffer(); synth->io_ops->synth_out(synth, synth->clear); } EXPORT_SYMBOL_GPL(spk_synth_flush);