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serial: atmel_serial: drop low-latency workaround

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Commit 1ecc26bd27 ("atmel_serial: split the interrupt handler") worked
around the infamous low_latency behaviour of tty_flip_buffer_push() by
dropping and reacquiring the port lock in the tasklet callback.

Since commit a9c3f68f3c ("tty: Fix low_latency BUG"),
tty_flip_buffer_push() always schedules a work item to push data to the
line discipline and there's no need to keep any low_latency hacks around.

Cc: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210421095509.3024-10-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2021-04-21 11:54:52 +02:00 committed by Greg Kroah-Hartman
parent e9af7e363a
commit 983fe58ad7
1 changed files with 0 additions and 18 deletions
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18
drivers/tty/serial/atmel_serial.c
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@ -1178,13 +1178,7 @@ static void atmel_rx_from_dma(struct uart_port *port)
1,
DMA_FROM_DEVICE);
/*
* Drop the lock here since it might end up calling
* uart_start(), which takes the lock.
*/
spin_unlock(&port->lock);
tty_flip_buffer_push(tport);
spin_lock(&port->lock);
atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT);
}
@ -1576,13 +1570,7 @@ static void atmel_rx_from_ring(struct uart_port *port)
uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg);
}
/*
* Drop the lock here since it might end up calling
* uart_start(), which takes the lock.
*/
spin_unlock(&port->lock);
tty_flip_buffer_push(&port->state->port);
spin_lock(&port->lock);
}
static void atmel_release_rx_pdc(struct uart_port *port)
@ -1667,13 +1655,7 @@ static void atmel_rx_from_pdc(struct uart_port *port)
}
} while (head >= pdc->dma_size);
/*
* Drop the lock here since it might end up calling
* uart_start(), which takes the lock.
*/
spin_unlock(&port->lock);
tty_flip_buffer_push(tport);
spin_lock(&port->lock);
atmel_uart_writel(port, ATMEL_US_IER,
ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);