Messages in this thread Patch in this message | | | Date | Sun, 26 Jun 2005 23:18:48 +0100 | From | Russell King <> | Subject | Re: [CFT:PATCH] 3/3: Disable OX950 transmitter for flow control |
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Disable the transmitter whenever we want to prevent characters being transmitted by flow control. However, if we run out of characters to send and want to only disable the TX interrupt, allow that scenario.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Index: drivers/serial/8250.c =================================================================== --- d1d56a4a3295f62a01fc06ffc764da474d2aa9b1/drivers/serial/8250.c (mode:100644) +++ uncommitted/drivers/serial/8250.c (mode:100644) @@ -1007,21 +1007,24 @@ up->port.irq = (irq > 0) ? irq : 0; } +static inline void __stop_tx(struct uart_8250_port *p) +{ + if (p->ier & UART_IER_THRI) { + p->ier &= ~UART_IER_THRI; + serial_out(p, UART_IER, p->ier); + } +} + static void serial8250_stop_tx(struct uart_port *port, unsigned int tty_stop) { struct uart_8250_port *up = (struct uart_8250_port *)port; - if (up->ier & UART_IER_THRI) { - up->ier &= ~UART_IER_THRI; - serial_out(up, UART_IER, up->ier); - } + __stop_tx(up); /* - * We only do this from uart_stop - if we run out of - * characters to send, we don't want to prevent the - * FIFO from emptying. + * We really want to stop the transmitter from sending. */ - if (up->port.type == PORT_16C950 && tty_stop) { + if (up->port.type == PORT_16C950) { up->acr |= UART_ACR_TXDIS; serial_icr_write(up, UART_ACR, up->acr); } @@ -1045,10 +1048,11 @@ transmit_chars(up); } } + /* - * We only do this from uart_start + * Re-enable the transmitter if we disabled it. */ - if (tty_start && up->port.type == PORT_16C950) { + if (up->port.type == PORT_16C950 && up->acr & UART_ACR_TXDIS) { up->acr &= ~UART_ACR_TXDIS; serial_icr_write(up, UART_ACR, up->acr); } @@ -1169,7 +1173,7 @@ return; } if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) { - serial8250_stop_tx(&up->port, 0); + __stop_tx(up); return; } @@ -1188,7 +1192,7 @@ DEBUG_INTR("THRE..."); if (uart_circ_empty(xmit)) - serial8250_stop_tx(&up->port, 0); + __stop_tx(up); } static _INLINE_ void check_modem_status(struct uart_8250_port *up) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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