# Software Flow Control Problem in UART.C

- From: Prabhakar Kalasani \<hidden\>
- Date: 2004-07-20 12:14:01 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2004/07/9394347
- Thread: https://ratatoskr.run/linuxppc-dev/2004/07/9394347/t.md

```text

Hi all,

When I tried to use Software Flow Control it's not working with uart.c
driver in kernel 2.4.2 , I send Ctrl+S character to stop the flow but the
flow is not get stopped ,
I dig something into driver and find like,

static void rs_8xx_stop(struct tty_struct *tty)
{

static void rs_8xx_start(struct tty_struct *tty)
{

these two modules are handling with the flow stop(Ctrl+S) and start(Ctrl+Q)
,
I think there is a BUG in handling the Event(SCCE) and Mask Registers (SCCM)
somewhere like

	if (info->state->smc_scc_num & NUM_IS_SCC) {
		sccp = &cpmp->cp_scc[idx];
		sccp->scc_sccm &= ~UART_SCCM_TX;

Anybody got this problem and solved please let me know

Thanks in Advance,
KP


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```