The KIOCSOUND and KDMKTONE ioctls are based on the CLOCK_TICK_RATE, which is architecture and sometimes configuration specific. In practice, most user applications assume that it is actually defined as the i8253 PIT base clock of 1193182 Hz, which is true on some architectures but not on others. This patch makes the vt code use the PIT frequency on all architectures, which is much more well-defined. It will change the behavior of user applications sending the beep ioctl on all architectures that define CLOCK_TICK_RATE different from PIT_TICK_RATE. The original breakage was introduced in commit bcc8ca099 "Adapt drivers/char/vt_ioctl.c to non-x86". Hopefully, reverting this change will make the frequency correct in more cases than it will make it incorrect. Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c index cb19dbc..592d8d1 100644 --- a/drivers/char/vt_ioctl.c +++ b/drivers/char/vt_ioctl.c @@ -533,11 +533,14 @@ int vt_ioctl(struct tty_struct *tty, struct file * file, case KIOCSOUND: if (!perm) goto eperm; - /* FIXME: This is an old broken API but we need to keep it - supported and somehow separate the historic advertised - tick rate from any real one */ + /* + * The use of PIT_TICK_RATE is historic, it used to be + * the platform-dependent CLOCK_TICK_RATE between 2.6.12 + * and 2.6.36, which was a minor but unfortunate ABI + * change. + */ if (arg) - arg = CLOCK_TICK_RATE / arg; + arg = PIT_TICK_RATE / arg; kd_mksound(arg, 0); break; @@ -553,11 +556,8 @@ int vt_ioctl(struct tty_struct *tty, struct file * file, */ ticks = HZ * ((arg >> 16) & 0xffff) / 1000; count = ticks ? (arg & 0xffff) : 0; - /* FIXME: This is an old broken API but we need to keep it - supported and somehow separate the historic advertised - tick rate from any real one */ if (count) - count = CLOCK_TICK_RATE / count; + count = PIT_TICK_RATE / count; kd_mksound(count, ticks); break; } -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
