>-----Original Message----- >From: Peter Hurley [mailto:peter@xxxxxxxxxxxxxxxxxx] >Sent: Friday, October 10, 2014 7:39 PM >To: Lu Jingchang-B35083; gregkh@xxxxxxxxxxxxxxxxxxx >Cc: arnd@xxxxxxxx; linux-serial@xxxxxxxxxxxxxxx; linux-arm- >kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Joseph Lo >Subject: Re: [PATCH] serial: of-serial: fix up PM ops on >no_console_suspend > >Hi Jingchang, > >On 10/09/2014 05:10 AM, Jingchang Lu wrote: >> Mandatorily disabling the uart clock will cause register access hung >> on "no_console_suspend". This patch add condition check on it and only >> disable the clock with console_suspend_enabled true. >> >> Signed-off-by: Joseph Lo <josephl@xxxxxxxxxx> >> Signed-off-by: Jingchang Lu <jingchang.lu@xxxxxxxxxxxxx> >> --- >> drivers/tty/serial/of_serial.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/tty/serial/of_serial.c >> b/drivers/tty/serial/of_serial.c index 8bc2563..a765399 100644 >> --- a/drivers/tty/serial/of_serial.c >> +++ b/drivers/tty/serial/of_serial.c >> @@ -246,7 +246,7 @@ static int of_serial_suspend(struct device *dev) >> struct of_serial_info *info = dev_get_drvdata(dev); >> >> serial8250_suspend_port(info->line); >> - if (info->clk) >> + if (info->clk && console_suspend_enabled) >> clk_disable_unprepare(info->clk); > >This needs to check that _this_ port is the console port, like: > > if (info->clk && uart_console(port) && and console_suspend_enabled) > clk_disable_unprepare(info->clk); > >which means you need something like: > > struct uart_8250_port *uart = serial8250_get_port(info->line); > struct uart_port *port = &uart->port; > >Also, there's another problem with your original patch: >not every of_serial device is an 8250, right? >serial8250_suspend_port() on a port that's not registered with 8250 core >is probably going to blow up. > >Which means the body of of_platform_suspend() and of_platform_resume() >should probably look like > > switch (info->type) { >#ifdef CONFIG_SERIAL_8250 > case PORT_8250 ... PORT_MAX_8250: > { > /* current body of function */ > } >#endif > default: > } > Yes, this should be considered, then serial8250_get_port(info->line) for uart_console() also should be put in this type switch, Thanks. Best Regards, Jingchang >Regards, >Peter Hurley > > >> >> return 0; >> @@ -256,7 +256,7 @@ static int of_serial_resume(struct device *dev) { >> struct of_serial_info *info = dev_get_drvdata(dev); >> >> - if (info->clk) >> + if (info->clk && console_suspend_enabled) >> clk_prepare_enable(info->clk); >> >> serial8250_resume_port(info->line); >> ��.n��������+%������w��{.n�����{��ǫ����{ay� ʇڙ���f���h������_�(�階�ݢj"��������G����?���&��
