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Commit 38f8eefc authored by Jason Wessel's avatar Jason Wessel Committed by Greg Kroah-Hartman
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pmac_zilog,kdb: Fix console poll hook to return instead of loop 



kdb <-> kgdb transitioning does not work properly with this UART
driver because the get character routine loops indefinitely as opposed
to returning NO_POLL_CHAR per the expectation of the KDB I/O driver
API.

The symptom is a kernel hang when trying to switch debug modes.

Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 00592021

drivers/tty/serial/pmac_zilog.c

+9 −3
Original line number Diff line number Diff line
@@ -1348,10 +1348,16 @@ static int pmz_verify_port(struct uart_port *port, struct serial_struct *ser) 
static int pmz_poll_get_char(struct uart_port *port)

{

	struct uart_pmac_port *uap = (struct uart_pmac_port *)port;

	int tries = 2;



	while ((read_zsreg(uap, R0) & Rx_CH_AV) == 0)

		udelay(5);

	while (tries) {

		if ((read_zsreg(uap, R0) & Rx_CH_AV) != 0)

			return read_zsdata(uap);

		if (tries--)

			udelay(5);

	}



	return NO_POLL_CHAR;

}



static void pmz_poll_put_char(struct uart_port *port, unsigned char c)