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Subject[PATCH v1] tty: serial: 8250_core: restore the LCR register in set_sleep
Date
In ST16650V2 based serial uarts, while initalizing the PM state,
LCR registers are being initialized to 0 in serial8250_set_sleep().
If console port is already initialized and being used, this will
throws garbage in the console.

Signed-off-by: Sudhir Sreedharan <ssreedharan@mvista.com>
---
Changes in v1:
Removed the condition of sleep flag for restoring the LCR and EFR.
Initialized the lcr and efr variables.

drivers/tty/serial/8250/8250_core.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index ca5cfdc..b170487 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -595,6 +595,7 @@ static void serial8250_rpm_put_tx(struct uart_8250_port *p)
*/
static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
{
+ unsigned char lcr = 0, efr = 0;
/*
* Exar UARTs have a SLEEP register that enables or disables
* each UART to enter sleep mode separately. On the XR17V35x the
@@ -611,6 +612,8 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)

if (p->capabilities & UART_CAP_SLEEP) {
if (p->capabilities & UART_CAP_EFR) {
+ lcr = serial_in(p, UART_LCR);
+ efr = serial_in(p, UART_EFR);
serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
serial_out(p, UART_EFR, UART_EFR_ECB);
serial_out(p, UART_LCR, 0);
@@ -618,8 +621,8 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
if (p->capabilities & UART_CAP_EFR) {
serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
- serial_out(p, UART_EFR, 0);
- serial_out(p, UART_LCR, 0);
+ serial_out(p, UART_EFR, efr);
+ serial_out(p, UART_LCR, lcr);
}
}
out:
--
1.7.0.1


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