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From:   Jiri Slaby <jslaby@suse.cz>
To:     gregkh@linuxfoundation.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jiri Slaby <jslaby@suse.cz>,
        Andrei Pistirica <andrei.pistirica@microchip.com>
Subject: [PATCH 11/11] serial: pic32: restore disabled irqs in pic32_uart_startup()
Date:   Tue,  3 May 2022 08:31:22 +0200
Message-Id: <20220503063122.20957-12-jslaby@suse.cz>
In-Reply-To: <20220503063122.20957-1-jslaby@suse.cz>
References: <20220503063122.20957-1-jslaby@suse.cz>
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pic32_uart_startup() disables interrupts by local_irq_save(). But the
function never enables them. The serial core only holds a mutex, so irqs
are not restored.

So how could this driver work? This irq handling was already present in
the driver's initial commit 157b9394709ed (serial: pic32_uart: Add PIC32
UART driver).

So is it a candidate for removal? Anyone has a contact to the author:
Andrei Pistirica (I believe the one below -- @microchip.com -- will
bounce)? Or to someone else @microchip.com?

Cc: Andrei Pistirica <andrei.pistirica@microchip.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/serial/pic32_uart.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/pic32_uart.c b/drivers/tty/serial/pic32_uart.c
index c5584628f8c4..b399aac530fe 100644
--- a/drivers/tty/serial/pic32_uart.c
+++ b/drivers/tty/serial/pic32_uart.c
@@ -564,6 +564,8 @@ static int pic32_uart_startup(struct uart_port *port)
 	/* enable all interrupts and eanable uart */
 	pic32_uart_en_and_unmask(port);
 
+	local_irq_restore(flags);
+
 	enable_irq(sport->irq_rx);
 
 	return 0;
-- 
2.36.0