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authorAri Entlich <atrigent@ccs.neu.edu>2010-02-19 09:37:55 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-03-02 14:43:23 -0800
commiteec9fe7d1ab4a0dfac4cb43047a7657fffd0002f (patch)
treeba6b4a517aaacbfde6e5496d02f97e6c9b491c2e /drivers/char/vt_ioctl.c
parentd9661adfb8e53a7647360140af3b92284cbe52d4 (diff)
downloadlinux-next-eec9fe7d1ab4a0dfac4cb43047a7657fffd0002f.tar.gz
tty: Add a new VT mode which is like VT_PROCESS but doesn't require a VT_RELDISP ioctl call
This new VT mode (VT_PROCESS_AUTO) does everything that VT_PROCESS does except that it doesn't wait for a VT_RELDISP ioctl before switching away from a VT with that mode. If the X server eventually uses this new mode, debugging and crash recovery should become easier. This is because even when currently in the VT of a frozen X server it would still be possible to switch out by doing SysRq-r and then CTRL-<number of a text vt>, sshing in and doing chvt <number of a text vt>, or any other method of VT switching. The general concensus on #xorg-devel seems to be that it should be safe to use this with X now that we have KMS. This also moves the VT_ACKACQ define to a more appropriate place, for clarity's sake. Signed-off-by: Ari Entlich <atrigent@ccs.neu.edu> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/char/vt_ioctl.c')
-rw-r--r--drivers/char/vt_ioctl.c39
1 files changed, 20 insertions, 19 deletions
diff --git a/drivers/char/vt_ioctl.c b/drivers/char/vt_ioctl.c
index 6aa10284104a..87778dcf8727 100644
--- a/drivers/char/vt_ioctl.c
+++ b/drivers/char/vt_ioctl.c
@@ -888,7 +888,7 @@ int vt_ioctl(struct tty_struct *tty, struct file * file,
ret = -EFAULT;
goto out;
}
- if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS) {
+ if (tmp.mode != VT_AUTO && tmp.mode != VT_PROCESS && tmp.mode != VT_PROCESS_AUTO) {
ret = -EINVAL;
goto out;
}
@@ -1622,7 +1622,7 @@ static void complete_change_console(struct vc_data *vc)
* telling it that it has acquired. Also check if it has died and
* clean up (similar to logic employed in change_console())
*/
- if (vc->vt_mode.mode == VT_PROCESS) {
+ if (vc->vt_mode.mode == VT_PROCESS || vc->vt_mode.mode == VT_PROCESS_AUTO) {
/*
* Send the signal as privileged - kill_pid() will
* tell us if the process has gone or something else
@@ -1682,7 +1682,7 @@ void change_console(struct vc_data *new_vc)
* vt to auto control.
*/
vc = vc_cons[fg_console].d;
- if (vc->vt_mode.mode == VT_PROCESS) {
+ if (vc->vt_mode.mode == VT_PROCESS || vc->vt_mode.mode == VT_PROCESS_AUTO) {
/*
* Send the signal as privileged - kill_pid() will
* tell us if the process has gone or something else
@@ -1693,27 +1693,28 @@ void change_console(struct vc_data *new_vc)
*/
vc->vt_newvt = new_vc->vc_num;
if (kill_pid(vc->vt_pid, vc->vt_mode.relsig, 1) == 0) {
+ if(vc->vt_mode.mode == VT_PROCESS)
+ /*
+ * It worked. Mark the vt to switch to and
+ * return. The process needs to send us a
+ * VT_RELDISP ioctl to complete the switch.
+ */
+ return;
+ } else {
/*
- * It worked. Mark the vt to switch to and
- * return. The process needs to send us a
- * VT_RELDISP ioctl to complete the switch.
+ * The controlling process has died, so we revert back to
+ * normal operation. In this case, we'll also change back
+ * to KD_TEXT mode. I'm not sure if this is strictly correct
+ * but it saves the agony when the X server dies and the screen
+ * remains blanked due to KD_GRAPHICS! It would be nice to do
+ * this outside of VT_PROCESS but there is no single process
+ * to account for and tracking tty count may be undesirable.
*/
- return;
+ reset_vc(vc);
}
/*
- * The controlling process has died, so we revert back to
- * normal operation. In this case, we'll also change back
- * to KD_TEXT mode. I'm not sure if this is strictly correct
- * but it saves the agony when the X server dies and the screen
- * remains blanked due to KD_GRAPHICS! It would be nice to do
- * this outside of VT_PROCESS but there is no single process
- * to account for and tracking tty count may be undesirable.
- */
- reset_vc(vc);
-
- /*
- * Fall through to normal (VT_AUTO) handling of the switch...
+ * Fall through to normal (VT_AUTO and VT_PROCESS_AUTO) handling of the switch...
*/
}