diff options
| author | Peter Hurley <peter@hurleysoftware.com> | 2015-03-09 14:05:01 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-03-26 22:21:08 +0100 |
| commit | f01a0bd8921b9d6668d41fae3198970e6318f532 (patch) | |
| tree | 6ab966e61fa6ba9963d5442b8bc56b653603bbd8 /drivers/tty | |
| parent | 509cb7dc07cc03c28c7995a9213a605c04675a58 (diff) | |
serial: 8250: Check UART_SCR is writable
Au1x00/RT2800+ doesn't implement the 8250 scratch register (and
this may be true of other h/w currently supported by the 8250 driver);
read back the canary value written to the scratch register to enable
the console h/w restart after resume from system suspend.
Fixes: 4516d50aabedb ("serial: 8250: Use canary to restart console ...")
Reported-by: Mason <slash.tmp@free.fr>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/8250/8250_core.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c index 0a8f11b69e68..3e7cf3711378 100644 --- a/drivers/tty/serial/8250/8250_core.c +++ b/drivers/tty/serial/8250/8250_core.c @@ -3585,7 +3585,8 @@ void serial8250_suspend_port(int line) port->type != PORT_8250) { unsigned char canary = 0xa5; serial_out(up, UART_SCR, canary); - up->canary = canary; + if (serial_in(up, UART_SCR) == canary) + up->canary = canary; } uart_suspend_port(&serial8250_reg, port); |