| Message ID | 1405081811-15254-1-git-send-email-daniel.thompson@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Fri, Jul 11, 2014 at 01:30:11PM +0100, Daniel Thompson wrote: > At present it is not possible to boot with the ttyNMI0 console treating > character input normally. To use the console requires that kdb be > entered and the nmi_console command be used to enable the console (or if > only kgdb is present then gdb must directly manipulate the value of > kgdb_nmi_tty_enabled). > > Introducing a module parameter makes the console much more usable. > > Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Jiri Slaby <jslaby@suse.cz> > Cc: linux-serial@vger.kernel.org > --- > drivers/tty/serial/kgdb_nmi.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/tty/serial/kgdb_nmi.c b/drivers/tty/serial/kgdb_nmi.c > index cfadf29..9361d69 100644 > --- a/drivers/tty/serial/kgdb_nmi.c > +++ b/drivers/tty/serial/kgdb_nmi.c > @@ -43,6 +43,11 @@ module_param_named(magic, kgdb_nmi_magic, charp, 0600); > MODULE_PARM_DESC(magic, "magic sequence to enter NMI debugger (default $3#33)"); > > static bool kgdb_nmi_tty_enabled; > +module_param_named(tty, kgdb_nmi_tty_enabled, bool, 0600); > +MODULE_PARM_DESC(tty, "if set to false (default), characters received from " > + "the UART will be passed exclusively to the knock " > + "detector; when set to true characters will be passed " > + "both to the knock detector and to the TTY layer"); Module options suck rocks through straws. Isn't there _any_ other way to determine this "dynamically"? How will someone know to set this option? Yeah, there are other options in this module, but please, why add more? greg k-h
On 12/07/14 01:47, Greg Kroah-Hartman wrote: > On Fri, Jul 11, 2014 at 01:30:11PM +0100, Daniel Thompson wrote: >> At present it is not possible to boot with the ttyNMI0 console treating >> character input normally. To use the console requires that kdb be >> entered and the nmi_console command be used to enable the console (or if >> only kgdb is present then gdb must directly manipulate the value of >> kgdb_nmi_tty_enabled). >> >> Introducing a module parameter makes the console much more usable. >> >> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> Cc: Jiri Slaby <jslaby@suse.cz> >> Cc: linux-serial@vger.kernel.org >> --- >> drivers/tty/serial/kgdb_nmi.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/drivers/tty/serial/kgdb_nmi.c b/drivers/tty/serial/kgdb_nmi.c >> index cfadf29..9361d69 100644 >> --- a/drivers/tty/serial/kgdb_nmi.c >> +++ b/drivers/tty/serial/kgdb_nmi.c >> @@ -43,6 +43,11 @@ module_param_named(magic, kgdb_nmi_magic, charp, 0600); >> MODULE_PARM_DESC(magic, "magic sequence to enter NMI debugger (default $3#33)"); >> >> static bool kgdb_nmi_tty_enabled; >> +module_param_named(tty, kgdb_nmi_tty_enabled, bool, 0600); >> +MODULE_PARM_DESC(tty, "if set to false (default), characters received from " >> + "the UART will be passed exclusively to the knock " >> + "detector; when set to true characters will be passed " >> + "both to the knock detector and to the TTY layer"); > > Module options suck rocks through straws. > > Isn't there _any_ other way to determine this "dynamically"? How will > someone know to set this option? > > Yeah, there are other options in this module, but please, why add more? Thanks for the comment. Yes. I think we can do this dynamically. The two modes currently offered are: 1. characters bypass TTY layer and knock detector interactively prompts for the knock ('Press $3#33 to enter debugger>') 2. characters are routed to TTY layer and to a (silenced) knock detector I think we might be able to select modes based on whether there is a userspace process reading from the tty (i.e. if there is a getty then act like a proper tty, if there is no getty allow prompting).
diff --git a/drivers/tty/serial/kgdb_nmi.c b/drivers/tty/serial/kgdb_nmi.c index cfadf29..9361d69 100644 --- a/drivers/tty/serial/kgdb_nmi.c +++ b/drivers/tty/serial/kgdb_nmi.c @@ -43,6 +43,11 @@ module_param_named(magic, kgdb_nmi_magic, charp, 0600); MODULE_PARM_DESC(magic, "magic sequence to enter NMI debugger (default $3#33)"); static bool kgdb_nmi_tty_enabled; +module_param_named(tty, kgdb_nmi_tty_enabled, bool, 0600); +MODULE_PARM_DESC(tty, "if set to false (default), characters received from " + "the UART will be passed exclusively to the knock " + "detector; when set to true characters will be passed " + "both to the knock detector and to the TTY layer"); static int kgdb_nmi_console_setup(struct console *co, char *options) {
At present it is not possible to boot with the ttyNMI0 console treating character input normally. To use the console requires that kdb be entered and the nmi_console command be used to enable the console (or if only kgdb is present then gdb must directly manipulate the value of kgdb_nmi_tty_enabled). Introducing a module parameter makes the console much more usable. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-serial@vger.kernel.org --- drivers/tty/serial/kgdb_nmi.c | 5 +++++ 1 file changed, 5 insertions(+)