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pmac_zilog,kdb: Fix console poll hook to return instead of loop

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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: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason Wessel 2012-08-12 07:16:43 -05:00 • committed by Greg Kroah-Hartman
parent 0059202101
commit 38f8eefccf
1 changed files with 9 additions and 3 deletions
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12
drivers/tty/serial/pmac_zilog.c
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@ -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) static int pmz_poll_get_char(struct uart_port *port)
{ {
struct uart_pmac_port *uap = (struct uart_pmac_port *)port; struct uart_pmac_port *uap = (struct uart_pmac_port *)port;
int tries = 2;
while ((read_zsreg(uap, R0) & Rx_CH_AV) == 0) while (tries) {
udelay(5); if ((read_zsreg(uap, R0) & Rx_CH_AV) != 0)
return read_zsdata(uap); 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) static void pmz_poll_put_char(struct uart_port *port, unsigned char c)