vt: Add a note on the historical abuse of CLOCK_TICK_RATE

This is one area where we can't just magic away the bizarre use of
CLOCK_TICK_RATE as it leaks to user space APIs. It also means the visible
CLOCK_TICK_RATE is frozen for architectures which is horrible.

We need to fix this somehow

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c
index a2dee0eb6dad..e6ce632a393e 100644
--- a/drivers/char/vt_ioctl.c
+++ b/drivers/char/vt_ioctl.c
@@ -400,6 +400,9 @@ 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 */
                 if (arg)
                         arg = CLOCK_TICK_RATE / arg;
                 kd_mksound(arg, 0);
@@ -417,6 +420,9 @@ 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;
                 kd_mksound(count, ticks);