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staging: speakup: flush tty buffers and ensure hardware flow control

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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 <covici@ccs.covici.com>
Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Okash Khawaja 2017-05-15 18:45:37 +01:00 committed by Greg Kroah-Hartman
parent 470790eefe
commit 1c5973675c
8 changed files with 42 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
drivers/staging/speakup/serialio.c
View file

@ -30,6 +30,7 @@ static void spk_serial_send_xchar(char ch);
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 @@ struct spk_io_ops spk_serial_io_ops = {
.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 @@ static unsigned char spk_serial_in_nowait(void)
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)) {

1
drivers/staging/speakup/speakup_audptr.c
View file

@ -127,6 +127,7 @@ static struct spk_synth synth_audptr = {
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);
}

1
drivers/staging/speakup/speakup_decext.c
View file

@ -221,6 +221,7 @@ static void do_catch_up(struct spk_synth *synth)
static void synth_flush(struct spk_synth *synth)
{
in_escape = 0;
synth->io_ops->flush_buffer();
synth->synth_immediate(synth, "\033P;10z\033\\");
}

1
drivers/staging/speakup/speakup_dectlk.c
View file

@ -293,6 +293,7 @@ static void synth_flush(struct spk_synth *synth)
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);
}

1
drivers/staging/speakup/speakup_spkout.c
View file

@ -125,6 +125,7 @@ static struct spk_synth synth_spkout = {
static void synth_flush(struct spk_synth *synth)
{
synth->io_ops->flush_buffer();
synth->io_ops->send_xchar(SYNTH_CLEAR);
}

29
drivers/staging/speakup/spk_ttyio.c
View file

@ -85,6 +85,7 @@ static void spk_ttyio_send_xchar(char ch);
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 @@ struct spk_io_ops spk_ttyio_ops = {
.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 @@ static int spk_ttyio_initialise_ldisc(int ser)
}
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 @@ static unsigned char spk_ttyio_in_nowait(void)
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);

1
drivers/staging/speakup/spk_types.h
View file

@ -154,6 +154,7 @@ struct spk_io_ops {
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 {

1
drivers/staging/speakup/synth.c
View file

@ -120,6 +120,7 @@ EXPORT_SYMBOL_GPL(spk_do_catch_up);
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);