On Fri, 1 May 2009 19:27:56 -0700
David VomLehn <dvomlehn@xxxxxxxxx> wrote:
> The patch has been re-written to use the init device synchronization
> infrastructure. This ensures that we can detect console
> initialization when the devices become available, as well as
> determining that no console is attached at boot time.
>
> History
> v5 Change bootdev_* to initdev_*.
> v4 Use new hotplug synchronization infrastructure. Include
> Braille console support.
> v3.2 Use only a single new command line parameter by adding
> the possible value "forever". Add message specifying the parameter
> to modify to increase the delay for console initialization
> v3.1 Correct the abbreviation for milliseconds in
> Documentation/kernel-parameters.txt to be "ms", not "mS".
> Thanks to Peter Anvin for this.
> v3 Increase the default delay to 1 second and add kernel
> command line parameters to override the default delay. Thanks to
> David Brownell for his helpful suggestions.
> v2 Wait for the preferred console rather than any console.
> Make the delay interval a tunable.
> v1 Initial version
>
> Signed-off-by: David VomLehn <dvomlehn@xxxxxxxxx>
> ---
> drivers/accessibility/braille/braille_console.c | 3 ++
> kernel/printk.c | 29
> ++++++++++++++++++++++- 2 files changed, 31 insertions(+), 1
> deletions(-)
>
> diff --git a/drivers/accessibility/braille/braille_console.c
> b/drivers/accessibility/braille/braille_console.c index
> d672cfe..4420ac3 100644 ---
> a/drivers/accessibility/braille/braille_console.c +++
> b/drivers/accessibility/braille/braille_console.c @@ -35,6 +35,7 @@
> #include <linux/keyboard.h>
> #include <linux/kbd_kern.h>
> #include <linux/input.h>
> +#include <linux/initdev.h>
>
> MODULE_AUTHOR("samuel.thibault@xxxxxxxxxxxx");
> MODULE_DESCRIPTION("braille device");
> @@ -378,6 +379,8 @@ int braille_register_console(struct console
> *console, int index, braille_co = console;
> register_keyboard_notifier(&keyboard_notifier_block);
> register_vt_notifier(&vt_notifier_block);
> +
> + initdev_register(BOOTDEV_CONSOLE);
Should it be initdev_registered(BOOTDEV_CONSOLE)?
> return 0;
> }
>
> diff --git a/kernel/printk.c b/kernel/printk.c
> index 5052b54..e6a9379 100644
> --- a/kernel/printk.c
> +++ b/kernel/printk.c
> @@ -33,6 +33,7 @@
> #include <linux/bootmem.h>
> #include <linux/syscalls.h>
> #include <linux/kexec.h>
> +#include <linux/device.h>
>
> #include <asm/uaccess.h>
>
> @@ -1075,8 +1076,10 @@ void console_unblank(void)
>
> /*
> * Return the console tty driver structure and its associated index
> + * @index: Pointer to the device index
> + * Returns NULL if no driver available, otherwise a pointer to the
> TTY driver. */
> -struct tty_driver *console_device(int *index)
> +struct tty_driver *_console_device(int *index)
> {
> struct console *c;
> struct tty_driver *driver = NULL;
> @@ -1094,6 +1097,29 @@ struct tty_driver *console_device(int *index)
> }
>
> /*
> + * Returns true if all specific consoles are registered, false
> otherwise
> + */
> +static bool have_all_consoles(void)
> +{
> + struct tty_driver *driver;
> + int index;
> +
> + driver = _console_device(&index);
> +
> + return driver != NULL;
> +}
> +
> +struct tty_driver *console_device(int *index)
> +{
> + struct tty_driver *driver;
> + initdev_wait(BOOTDEV_CONSOLE, have_all_consoles);
> +
> + driver = _console_device(index);
> +
> + return driver;
> +}
> +
> +/*
> * Prevent further output on the passed console device so that (for
> example)
> * serial drivers can disable console output before suspending a
> port, and can
> * re-enable output afterwards.
> @@ -1230,6 +1256,7 @@ void register_console(struct console *console)
> spin_unlock_irqrestore(&logbuf_lock, flags);
> }
> release_console_sem();
> + initdev_registered(BOOTDEV_CONSOLE);
> }
> EXPORT_SYMBOL(register_console);
>
> --
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--
Lei Ming
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