diff options
| author | Peter Collingbourne <pcc@google.com> | 2024-02-22 11:26:34 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-03-02 22:11:03 +0100 |
| commit | e5d6bd25f93d6ae158bb4cd04956cb497a85b8ef (patch) | |
| tree | 8430541d7e01f075d70bd4d78f982d624d4f9a30 | |
| parent | 672448ccf9b6a676f96f9352cbf91f4d35f4084a (diff) | |
| download | linux-e5d6bd25f93d6ae158bb4cd04956cb497a85b8ef.tar.gz | |
serial: 8250_dw: Do not reclock if already at correct rate
When userspace opens the console, we call set_termios() passing a
termios with the console's configured baud rate. Currently this causes
dw8250_set_termios() to disable and then re-enable the UART clock at
the same frequency as it was originally. This can cause corruption
of any concurrent console output. Fix it by skipping the reclocking
if we are already at the correct rate.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Fixes: 4e26b134bd17 ("serial: 8250_dw: clock rate handling for all ACPI platforms")
Cc: stable@vger.kernel.org
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240222192635.1050502-1-pcc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/8250/8250_dw.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index 2d1f350a4bea2a..c1d43f040c43ab 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -357,9 +357,9 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios, long rate; int ret; - clk_disable_unprepare(d->clk); rate = clk_round_rate(d->clk, newrate); - if (rate > 0) { + if (rate > 0 && p->uartclk != rate) { + clk_disable_unprepare(d->clk); /* * Note that any clock-notifer worker will block in * serial8250_update_uartclk() until we are done. @@ -367,8 +367,8 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios, ret = clk_set_rate(d->clk, newrate); if (!ret) p->uartclk = rate; + clk_prepare_enable(d->clk); } - clk_prepare_enable(d->clk); dw8250_do_set_termios(p, termios, old); } |