diff options
| -rw-r--r-- | drivers/char/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/char/hvc_console.c | 56 |
2 files changed, 42 insertions, 18 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 1232ace097e..57b801716fb 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -585,8 +585,8 @@ config TIPAR config HVC_DRIVER bool help - Users of pSeries machines that want to utilize the hvc console front-end - module for their backend console driver should select this option. + Generic "hypervisor virtual console" infrastructure for various + hypervisors (pSeries, Xen, lguest). It will automatically be selected if one of the back-end console drivers is selected. diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c index 83c1151ec7a..8252f866853 100644 --- a/drivers/char/hvc_console.c +++ b/drivers/char/hvc_console.c @@ -69,6 +69,8 @@ static struct task_struct *hvc_task; /* Picks up late kicks after list walk but before schedule() */ static int hvc_kicked; +static int hvc_init(void); + #ifdef CONFIG_MAGIC_SYSRQ static int sysrq_pressed; #endif @@ -754,6 +756,13 @@ struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq, struct hvc_struct *hp; int i; + /* We wait until a driver actually comes along */ + if (!hvc_driver) { + int err = hvc_init(); + if (err) + return ERR_PTR(err); + } + hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, GFP_KERNEL); if (!hp) @@ -829,16 +838,18 @@ int __devexit hvc_remove(struct hvc_struct *hp) return 0; } -/* Driver initialization. Follow console initialization. This is where the TTY - * interfaces start to become available. */ -static int __init hvc_init(void) +/* Driver initialization: called as soon as someone uses hvc_alloc(). */ +static int hvc_init(void) { struct tty_driver *drv; + int err; /* We need more than hvc_count adapters due to hotplug additions. */ drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); - if (!drv) - return -ENOMEM; + if (!drv) { + err = -ENOMEM; + goto out; + } drv->owner = THIS_MODULE; drv->driver_name = "hvc"; @@ -854,30 +865,43 @@ static int __init hvc_init(void) * added later. */ hvc_task = kthread_run(khvcd, NULL, "khvcd"); if (IS_ERR(hvc_task)) { - panic("Couldn't create kthread for console.\n"); - put_tty_driver(drv); - return -EIO; + printk(KERN_ERR "Couldn't create kthread for console.\n"); + err = PTR_ERR(hvc_task); + goto put_tty; } - if (tty_register_driver(drv)) - panic("Couldn't register hvc console driver\n"); + err = tty_register_driver(drv); + if (err) { + printk(KERN_ERR "Couldn't register hvc console driver\n"); + goto stop_thread; + } + /* FIXME: This mb() seems completely random. Remove it. */ mb(); hvc_driver = drv; return 0; + +put_tty: + put_tty_driver(hvc_driver); +stop_thread: + kthread_stop(hvc_task); + hvc_task = NULL; +out: + return err; } -module_init(hvc_init); /* This isn't particularly necessary due to this being a console driver * but it is nice to be thorough. */ static void __exit hvc_exit(void) { - kthread_stop(hvc_task); + if (hvc_driver) { + kthread_stop(hvc_task); - tty_unregister_driver(hvc_driver); - /* return tty_struct instances allocated in hvc_init(). */ - put_tty_driver(hvc_driver); - unregister_console(&hvc_con_driver); + tty_unregister_driver(hvc_driver); + /* return tty_struct instances allocated in hvc_init(). */ + put_tty_driver(hvc_driver); + unregister_console(&hvc_con_driver); + } } module_exit(hvc_exit); |