Commit f9f54983 authored by Ulrich Hecht's avatar Ulrich Hecht Committed by Greg Kroah-Hartman
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serial: sh-sci: remove obsolete latency workaround 



Since the transition to hrtimers there is no more need to set a minimum
RX timeout to work around latency issues.

Reviewed-by: default avatarYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: default avatarUlrich Hecht <uli+renesas@fpond.eu>
Link: https://lore.kernel.org/r/20210415093547.21639-1-uli+renesas@fpond.eu


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5ffa6e34

drivers/tty/serial/sh-sci.c

+1 −12
Original line number Diff line number Diff line
@@ -2609,21 +2609,10 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, 
		udelay(DIV_ROUND_UP(10 * 1000000, baud));

	}



	/*

	 * Calculate delay for 2 DMA buffers (4 FIFO).

	 * See serial_core.c::uart_update_timeout().

	 * With 10 bits (CS8), 250Hz, 115200 baud and 64 bytes FIFO, the above

	 * function calculates 1 jiffie for the data plus 5 jiffies for the

	 * "slop(e)." Then below we calculate 5 jiffies (20ms) for 2 DMA

	 * buffers (4 FIFO sizes), but when performing a faster transfer, the

	 * value obtained by this formula is too small. Therefore, if the value

	 * is smaller than 20ms, use 20ms as the timeout value for DMA.

	 */

	/* Calculate delay for 2 DMA buffers (4 FIFO). */

	s->rx_frame = (10000 * bits) / (baud / 100);

#ifdef CONFIG_SERIAL_SH_SCI_DMA

	s->rx_timeout = s->buf_len_rx * 2 * s->rx_frame;

	if (s->rx_timeout < 20)

		s->rx_timeout = 20;

#endif



	if ((termios->c_cflag & CREAD) != 0)