[PATCH] linux: Use K_OFF VT KB mode over K_RAW if available.
Arthur Taylor
art at ified.ca
Thu Jan 5 23:21:37 PST 2012
Linux kernels since 2.6.38 (March 2011) have an VT KB mode K_OFF in
which special keys (like Ctrl+C) are not interpreted and input is not
buffered. Use of this mode over K_RAW removes the need for a
xf86ConsoleHandler to drain the VT input buffer, removing the grief it
causes when it goes wrong or is (de)initialized out-of-order. (This
also saves a few needless context switches per key event.)
If K_OFF is not defined or not understood by the kernel, K_RAW and the
previous method is used as a fall-back.
Signed-off-by: Arthur Taylor <art at ified.ca>
---
hw/xfree86/os-support/linux/lnx_init.c | 19 +++++++++++++------
1 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/hw/xfree86/os-support/linux/lnx_init.c b/hw/xfree86/os-support/linux/lnx_init.c
index 5f3e3a9..699e8c5 100644
--- a/hw/xfree86/os-support/linux/lnx_init.c
+++ b/hw/xfree86/os-support/linux/lnx_init.c
@@ -212,10 +212,20 @@ xf86OpenConsole(void)
tcgetattr(xf86Info.consoleFd, &tty_attr);
SYSCALL(ioctl(xf86Info.consoleFd, KDGKBMODE, &tty_mode));
- SYSCALL(ret = ioctl(xf86Info.consoleFd, KDSKBMODE, K_RAW));
+#ifdef K_OFF
+ /* disable kernel special keys and buffering */
+ SYSCALL(ret = ioctl(xf86Info.consoleFd, KDSKBMODE, K_OFF));
if (ret < 0)
- FatalError("xf86OpenConsole: KDSKBMODE K_RAW failed %s\n",
- strerror(errno));
+#endif
+ {
+ SYSCALL(ret = ioctl(xf86Info.consoleFd, KDSKBMODE, K_RAW));
+ if (ret < 0)
+ FatalError("xf86OpenConsole: KDSKBMODE K_RAW failed %s\n",
+ strerror(errno));
+
+ /* need to keep the buffer clean, else the kernel gets angry */
+ xf86SetConsoleHandler(drain_console, NULL);
+ }
nTty = tty_attr;
nTty.c_iflag = (IGNPAR | IGNBRK) & (~PARMRK) & (~ISTRIP);
@@ -228,9 +238,6 @@ xf86OpenConsole(void)
cfsetospeed(&nTty, 9600);
tcsetattr(xf86Info.consoleFd, TCSANOW, &nTty);
- /* need to keep the buffer clean, else the kernel gets angry */
- xf86SetConsoleHandler(drain_console, NULL);
-
/* we really should have a InitOSInputDevices() function instead
* of Init?$#*&Device(). So I just place it here */
}
--
1.7.8.2
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