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[drivers][serial] improve TIOCGWINSZ and termios updates #11891

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b717951
[drivers][serial] improve TIOCGWINSZ and termios updates
BernardXiong Oct 18, 2026
390c395
[drivers][serial] apply clang-format to TIOCGWINSZ changes
BernardXiong Oct 18, 2026
cd8ac61
[drivers][serial] use tick delta and non-blocking TIOCGWINSZ query
BernardXiong Oct 25, 2026
1bcfeb6
[drivers][serial] skip redundant UART configure for termios changes
BernardXiong Oct 31, 2026
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118 changes: 48 additions & 70 deletions components/drivers/serial/dev_serial.c
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@
#include <rtdbg.h>

#ifdef RT_USING_POSIX_STDIO
#include <stdlib.h>
#include <dfs_file.h>
#include <fcntl.h>
#include <unistd.h>
Expand Down Expand Up @@ -1339,12 +1340,16 @@ static rt_err_t rt_serial_control(struct rt_device *dev,
}
else config.parity = PARITY_NONE;

ret = serial->ops->configure(serial, &config);
if (ret != RT_EOK)
/* Software-only termios changes must not reset the UART FIFO. */
if (rt_memcmp(&config, &serial->config, sizeof(config)) != 0)
Comment on lines +1343 to +1344

@rcitach rcitach Oct 28, 2026 •
edited
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v2 版本是否也需要添加该逻辑

@BernardXiong BernardXiong Oct 31, 2026

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已同步到 v2（commit 1bcfeb6）：dev_serial_v2.c 的 TCSETS/TCSETSW/TCSETSF 路径现在也会先比较新配置与 serial->config，没有变化就跳过 ops->configure()，避免仅修改软件 termios（如 ONLCR/ICANON）时重新配置 UART 并重置 FIFO。

{
return ret;
ret = serial->ops->configure(serial, &config);
if (ret != RT_EOK)
{
return ret;
}
serial->config = config;
}
serial->config = config;
}
break;
#ifndef RT_USING_TTY
Expand All @@ -1370,85 +1375,58 @@ static rt_err_t rt_serial_control(struct rt_device *dev,
break;
case TIOCGWINSZ:
{
struct winsize* p_winsize;
p_winsize = (struct winsize*)args;

if(rt_thread_self() != rt_thread_find("tshell"))
struct winsize *winsize = (struct winsize *)args;
char response[32] = { 0 };
const char query[] = "\033[18t";
rt_tick_t start_tick;
rt_size_t i = 0;
unsigned long rows, columns;
char *end;

if (winsize == RT_NULL)
{
/* only can be used in tshell thread; otherwise, return default size */
p_winsize->ws_col = 80;
p_winsize->ws_row = 24;
ret = -RT_EINVAL;
break;
}
else
{
#include <shell.h>
#define _TIO_BUFLEN 20
char _tio_buf[_TIO_BUFLEN];
unsigned char cnt1, cnt2, cnt3, i;
char row_s[4], col_s[4];
char *p;

rt_memset(_tio_buf, 0, _TIO_BUFLEN);
rt_memset(winsize, 0, sizeof(*winsize));
winsize->ws_row = 24;
winsize->ws_col = 80;
rt_device_write(dev, -1, query, sizeof(query) - 1);

/* send the command to terminal for getting the window size of the terminal */
rt_kprintf("\033[18t");

/* waiting for the response from the terminal */
i = 0;
while(i < _TIO_BUFLEN)
start_tick = rt_tick_get();
while (i < sizeof(response) - 1 &&
rt_tick_get_delta(start_tick) < rt_tick_from_millisecond(200))
{
if (rt_device_read(dev, -1, &response[i], 1) == 1)
{
_tio_buf[i] = finsh_getchar();
if(_tio_buf[i] != 't')
{
i ++;
}
else
if (response[i++] == 't')
{
break;
}
}
if(i == _TIO_BUFLEN)
{
/* buffer overloaded, and return default size */
p_winsize->ws_col = 80;
p_winsize->ws_row = 24;
break;
}

/* interpreting data eg: "\033[8;1;15t" which means row is 1 and col is 15 (unit: size of ONE character) */
rt_memset(row_s,0,4);
rt_memset(col_s,0,4);
cnt1 = 0;
while(cnt1 < _TIO_BUFLEN && _tio_buf[cnt1] != ';')
{
cnt1++;
}
cnt2 = ++cnt1;
while(cnt2 < _TIO_BUFLEN && _tio_buf[cnt2] != ';')
{
cnt2++;
}
p = row_s;
while(cnt1 < cnt2)
{
*p++ = _tio_buf[cnt1++];
}
p = col_s;
cnt2++;
cnt3 = rt_strlen(_tio_buf) - 1;
while(cnt2 < cnt3)
else
{
*p++ = _tio_buf[cnt2++];
rt_thread_mdelay(1);
}

/* load the window size date */
p_winsize->ws_col = atoi(col_s);
p_winsize->ws_row = atoi(row_s);
#undef _TIO_BUFLEN
}

p_winsize->ws_xpixel = 0;/* unused */
p_winsize->ws_ypixel = 0;/* unused */
if (rt_memcmp(response, "\033[8;", 4) != 0)
{
break;
}
rows = strtoul(response + 4, &end, 10);
if (*end != ';')
{
break;
}
columns = strtoul(end + 1, &end, 10);
if (*end == 't' && end[1] == '\0' &&
rows != 0 && rows <= 999 && columns != 0 && columns <= 999)
{
winsize->ws_row = rows;
winsize->ws_col = columns;
}
}
break;
case FIONREAD:
Expand Down
133 changes: 64 additions & 69 deletions components/drivers/serial/dev_serial_v2.c
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Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@
#endif /* RT_SERIAL_BUF_STRATEGY_DROP */

#ifdef RT_USING_POSIX_STDIO
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
Expand Down Expand Up @@ -1843,13 +1844,17 @@ static rt_err_t rt_serial_control(struct rt_device *dev,
else
config.flowcontrol = RT_SERIAL_FLOWCONTROL_NONE;

ret = serial->ops->configure(serial, &config);
if (ret != RT_EOK)
/* Software-only termios changes must not reset the UART FIFO. */
if (rt_memcmp(&config, &serial->config, sizeof(config)) != 0)
{
break;
ret = serial->ops->configure(serial, &config);
if (ret != RT_EOK)
{
break;
}
/* set serial configure */
serial->config = config;
}
/* set serial configure */
serial->config = config;
}
break;
case TCFLSH:
Expand All @@ -1873,85 +1878,75 @@ static rt_err_t rt_serial_control(struct rt_device *dev,
break;
case TIOCGWINSZ:
{
struct winsize *p_winsize;
p_winsize = (struct winsize *)args;

if (rt_thread_self() != rt_thread_find(FINSH_THREAD_NAME))
struct winsize *winsize = (struct winsize *)args;
char response[32] = { 0 };
const char query[] = "\033[18t";
rt_tick_t start_tick;
rt_size_t i = 0;
unsigned long rows, columns;
char *end;
rt_int32_t old_rx_timeout;
rt_int32_t no_wait_timeout = RT_WAITING_NO;
rt_bool_t rx_timeout_changed = RT_FALSE;

if (winsize == RT_NULL)
{
/* only can be used in tshell thread; otherwise, return default size */
p_winsize->ws_col = 80;
p_winsize->ws_row = 24;
ret = -RT_EINVAL;
break;
}
else
{
#include <shell.h>
#define _TIO_BUFLEN 20
char _tio_buf[_TIO_BUFLEN];
unsigned char cnt1, cnt2, cnt3, i;
char row_s[4], col_s[4];
char *p;

rt_memset(_tio_buf, 0, _TIO_BUFLEN);
rt_memset(winsize, 0, sizeof(*winsize));
winsize->ws_row = 24;
winsize->ws_col = 80;

/* A blocking serial read waits forever if the terminal does not
* answer; make the query non-blocking for its duration. */
if (rt_device_control(dev, RT_SERIAL_CTRL_GET_RX_TIMEOUT, &old_rx_timeout) == RT_EOK &&
rt_device_control(dev, RT_SERIAL_CTRL_SET_RX_TIMEOUT, &no_wait_timeout) == RT_EOK)
{
rx_timeout_changed = RT_TRUE;
}

/* send the command to terminal for getting the window size of the terminal */
rt_kprintf("\033[18t");
rt_device_write(dev, -1, query, sizeof(query) - 1);

/* waiting for the response from the terminal */
i = 0;
while (i < _TIO_BUFLEN)
start_tick = rt_tick_get();
while (i < sizeof(response) - 1 &&
rt_tick_get_delta(start_tick) < rt_tick_from_millisecond(200))
{
if (rt_device_read(dev, -1, &response[i], 1) == 1)

@Ryan-CW-Code Ryan-CW-Code Oct 22, 2026

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是否需要判断之前是否设置过O_NONBLOCK，v2默认read是永久等待

@BernardXiong BernardXiong Oct 25, 2026

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已处理，commit cd8ac61。

  • v1 的 _serial_poll_rx() 本身是非阻塞的，问题只在 v2：RT_SERIAL_RX_BLOCKING 下 rx_timeout 默认是 RT_WAITING_FOREVER，单次 rt_device_read() 可能永久阻塞，而 200 ms 的 tick 检查只在两次 read 之间生效。
  • 现在查询期间通过 RT_SERIAL_CTRL_GET_RX_TIMEOUT / RT_SERIAL_CTRL_SET_RX_TIMEOUT 保存并切到 RT_WAITING_NO，循环结束后恢复原值；poll 模式（rx_bufsz == 0）下这两个命令返回 -RT_EPERM，保持原有的非阻塞行为。
  • 没有直接判断 O_NONBLOCK：这里是直接操作 device，而不是 fd，O_NONBLOCK 属于 fd 层状态；保存/恢复设备层 rx_timeout 更直接，也不会重新配置 UART。

{
_tio_buf[i] = finsh_getchar();
if (_tio_buf[i] != 't')
{
i++;
}
else
if (response[i++] == 't')
{
break;
}
}
if (i == _TIO_BUFLEN)
{
/* buffer overloaded, and return default size */
p_winsize->ws_col = 80;
p_winsize->ws_row = 24;
break;
}

/* interpreting data eg: "\033[8;1;15t" which means row is 1 and col is 15 (unit: size of ONE character) */
rt_memset(row_s, 0, 4);
rt_memset(col_s, 0, 4);
cnt1 = 0;
while (cnt1 < _TIO_BUFLEN && _tio_buf[cnt1] != ';')
{
cnt1++;
}
cnt2 = ++cnt1;
while (cnt2 < _TIO_BUFLEN && _tio_buf[cnt2] != ';')
{
cnt2++;
}
p = row_s;
while (cnt1 < cnt2)
{
*p++ = _tio_buf[cnt1++];
}
p = col_s;
cnt2++;
cnt3 = rt_strlen(_tio_buf) - 1;
while (cnt2 < cnt3)
else
{
*p++ = _tio_buf[cnt2++];
rt_thread_mdelay(1);
}
}

/* load the window size date */
p_winsize->ws_col = atoi(col_s);
p_winsize->ws_row = atoi(row_s);
#undef _TIO_BUFLEN
if (rx_timeout_changed)
{
rt_device_control(dev, RT_SERIAL_CTRL_SET_RX_TIMEOUT, &old_rx_timeout);
}

p_winsize->ws_xpixel = 0; /* unused */
p_winsize->ws_ypixel = 0; /* unused */
if (rt_memcmp(response, "\033[8;", 4) != 0)
{
break;
}
rows = strtoul(response + 4, &end, 10);
if (*end != ';')
{
break;
}
columns = strtoul(end + 1, &end, 10);
if (*end == 't' && end[1] == '\0' &&
rows != 0 && rows <= 999 && columns != 0 && columns <= 999)
{
winsize->ws_row = rows;
winsize->ws_col = columns;
}
}
break;
case FIONREAD:
Expand Down
38 changes: 24 additions & 14 deletions components/drivers/serial/serial_tty.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,8 @@
#include <rtdevice.h>
#include <terminal/terminal.h>

#include <sys/ioctl.h>

#define TTY_NAME_PREFIX "S" /* (S)erial */
#define LWP_TTY_WORKQUEUE_PRIORITY 3

Expand Down Expand Up @@ -159,6 +161,19 @@ static void _serial_tty_set_speed(struct lwp_tty *tp)
tp->t_termios_init_in.__c_ispeed = tp->t_termios_init_in.__c_ospeed = cfgetospeed(&tp->t_termios_init_in);
}

static void _serial_tty_update_winsize(struct lwp_tty *tp,
struct rt_serial_device *serial)
{
struct winsize winsz;

rt_memset(&winsz, 0, sizeof(winsz));
if (rt_device_control(&serial->parent, TIOCGWINSZ, &winsz) == RT_EOK &&
winsz.ws_row != 0 && winsz.ws_col != 0)
{
tp->t_winsize = winsz;
}
}

static int _serial_isbusy(struct rt_serial_device *serial)
{
rt_thread_t user_thread = rt_console_current_user();
Expand Down Expand Up @@ -222,6 +237,13 @@ static int serial_tty_open(struct lwp_tty *tp)
* to avoid driver accesssing null data,
* these are setup only after tty is registered
*/
if (rt_console_get_device() == &serial->parent)
{
/* Query before the bypass is installed so the response stays in
* the raw serial receive queue instead of being delivered as
* input. */
_serial_tty_update_winsize(tp, serial);
}
_setup_serial(serial, tp, softc);
}
return error;
Expand All @@ -243,20 +265,8 @@ static void serial_tty_close(struct lwp_tty *tp)
static int serial_tty_ioctl(struct lwp_tty *tp, rt_ubase_t cmd, rt_caddr_t data,
struct rt_thread *td)
{
int error;
switch (cmd)
{
default:
/**
* Note: for the most case, we don't let serial layer handle ioctl,
* for that they can't act properly regarding to the process
* management system, since it is unawared of that. So a ENOSYS is
* returned and caused the TTY layer to handle ioctl itself.
*/
error = -ENOSYS;
break;
}
return error;
/* Let the TTY layer handle process state and cached terminal settings. */
return -ENOSYS;
}

static int serial_tty_param(struct lwp_tty *tp, struct termios *t)
Expand Down
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