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Message-Id: <20250506112321.61710-4-cuiyunhui@bytedance.com>
Date: Tue, 6 May 2025 19:23:21 +0800
From: Yunhui Cui <cuiyunhui@...edance.com>
To: arnd@...db.de,
andriy.shevchenko@...ux.intel.com,
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Subject: [PATCH v5 4/4] serial: 8250_dw: fix PSLVERR on RX_TIMEOUT
In the case of RX_TIMEOUT, to avoid PSLVERR, disable the FIFO
before reading UART_RX when UART_LSR_DR is not set.
Fixes: 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt")
Signed-off-by: Yunhui Cui <cuiyunhui@...edance.com>
---
drivers/tty/serial/8250/8250_dw.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index f41c4a9ed58b..ffa8cb10b39c 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -288,9 +288,17 @@ static int dw8250_handle_irq(struct uart_port *p)
uart_port_lock_irqsave(p, &flags);
status = serial_lsr_in(up);
- if (!(status & (UART_LSR_DR | UART_LSR_BI)))
+ if (!(status & (UART_LSR_DR | UART_LSR_BI))) {
+ /* To avoid PSLVERR, disable the FIFO first. */
+ if (up->fcr & UART_FCR_ENABLE_FIFO)
+ serial_out(up, UART_FCR, 0);
+
(void) p->serial_in(p, UART_RX);
+ if (up->fcr & UART_FCR_ENABLE_FIFO)
+ serial_out(up, UART_FCR, up->fcr);
+ }
+
uart_port_unlock_irqrestore(p, flags);
}
--
2.39.2
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