Commit c9f49e3e authored by John Ogness's avatar John Ogness Committed by Greg Kroah-Hartman
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serial: 8250: Use @ier bits to determine if Rx is stopped 



Commit f19c3f6c ("serial: 8250_port: Don't service RX FIFO if
throttled") uses @read_status_mask (bit UART_LSR_DR) to determine
if Rx has been stopped. However, the bit UART_LSR_DR is not
managed properly in @read_status_mask for all Rx stop/start
situations and is therefore not suitable for this purpose.

Use the UART_IER_RLSI and UART_IER_RDI bits in @ier instead, as
this is already common in 8250-variants and drivers.

Signed-off-by: default avatarJohn Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/r/20241216171244.12783-2-john.ogness@linutronix.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e95cb63e

drivers/tty/serial/8250/8250_port.c

+1 −1
Original line number Diff line number Diff line
@@ -1931,7 +1931,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir) 
	 */

	if (!(status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) &&

	    (port->status & (UPSTAT_AUTOCTS | UPSTAT_AUTORTS)) &&

	    !(port->read_status_mask & UART_LSR_DR))

	    !(up->ier & (UART_IER_RLSI | UART_IER_RDI)))

		skip_rx = true;



	if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) {