diff options
Diffstat (limited to 'drivers/tty/hvc/hvc_dcc.c')
| -rw-r--r-- | drivers/tty/hvc/hvc_dcc.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/tty/hvc/hvc_dcc.c b/drivers/tty/hvc/hvc_dcc.c index 44fbebab5075..3502a7bbb69e 100644 --- a/drivers/tty/hvc/hvc_dcc.c +++ b/drivers/tty/hvc/hvc_dcc.c @@ -86,6 +86,21 @@ static int hvc_dcc_get_chars(uint32_t vt, char *buf, int count) return i; } +static bool hvc_dcc_check(void) +{ + unsigned long time = jiffies + (HZ / 10); + + /* Write a test character to check if it is handled */ + __dcc_putchar('\n'); + + while (time_is_after_jiffies(time)) { + if (!(__dcc_getstatus() & DCC_STATUS_TX)) + return true; + } + + return false; +} + static const struct hv_ops hvc_dcc_get_put_ops = { .get_chars = hvc_dcc_get_chars, .put_chars = hvc_dcc_put_chars, @@ -93,6 +108,9 @@ static const struct hv_ops hvc_dcc_get_put_ops = { static int __init hvc_dcc_console_init(void) { + if (!hvc_dcc_check()) + return -ENODEV; + hvc_instantiate(0, 0, &hvc_dcc_get_put_ops); return 0; } @@ -100,6 +118,9 @@ console_initcall(hvc_dcc_console_init); static int __init hvc_dcc_init(void) { + if (!hvc_dcc_check()) + return -ENODEV; + hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128); return 0; } |