我已配置kdm（编辑/usr/share/config/kdm/kdmrc）自动打开两个显示器：StaticServers=:0,:1。当我用Ctrl++在Alt它们之间切换时F7-8，有大约2秒的延迟，这非常烦人。
startx当我直接从tty没有干预的情况下，也会发生同样的情况kdm。如果我更改窗口管理器（如openbox或twm），问题仍然存在。
我怎样才能使这种切换尽可能瞬时？
$ lsmod | grep kms
drm_kms_helper 49262 1 i915
drm 258005 12 i915,drm_kms_helper
i2c_core 50152 5 drm,i915,i2c_i801,drm_kms_helper,i2c_algo_bit
$ uname -a
Linux hostname 3.16.4-1-ARCH #1 SMP PREEMPT Mon Oct 6 08:22:27 CEST 2014 x86_64 GNU/Linux
$ lspci |grep -e VGA -e 3D
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09)
$ grep -e driver /var/log/Xorg.0.log
[ 4.624] X.Org XInput driver : 21.0
[ 4.627] (==) Matched intel as autoconfigured driver 0
[ 4.627] (==) Matched modesetting as autoconfigured driver 1
[ 4.627] (==) Matched fbdev as autoconfigured driver 2
[ 4.627] (==) Matched vesa as autoconfigured driver 3
[ 4.627] (==) Assigned the driver to the xf86ConfigLayout
[ 4.627] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so
[ 4.962] (II) intel(0): Using Kernel Mode Setting driver: i915, version 1.6.0 20080730
[ 4.964] (II) intel(0): [DRI2] DRI driver: i965
[ 4.964] (II) intel(0): [DRI2] VDPAU driver: i965
[ 5.032] ABI class: X.Org XInput driver, version 21.0
[ 5.032] (II) Using input driver 'evdev' for 'Power Button'
[ 5.053] (II) Using input driver 'evdev' for 'Video Bus'
[ 5.053] (II) Using input driver 'evdev' for 'Power Button'
[ 5.054] (II) Using input driver 'evdev' for 'Forward USB Optical Mouse'
[ 5.055] (II) No input driver specified, ignoring this device.
[ 5.055] (II) Using input driver 'evdev' for 'Microsoft Comfort Mouse 6000'
[ 5.056] (II) No input driver specified, ignoring this device.
[ 5.056] (II) Using input driver 'evdev' for 'Microsoft Natural® Ergonomic Keyboard 4000'
[ 5.057] (II) Using input driver 'evdev' for 'Microsoft Natural® Ergonomic Keyboard 4000'
[ 5.057] (II) No input driver specified, ignoring this device.
$ dmesg | grep drm
[ 2.696528] [drm] Initialized drm 1.1.0 20060810
[ 2.793949] [drm] Memory usable by graphics device = 2048M
2.793951] [drm] Replacing VGA console driver
2.793955] fb: switching to inteldrmfb from VESA VGA
2.813970] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
2.813971] [drm] Driver supports precise vblank timestamp query.
[ 2.890589] [drm] GMBUS [i915 gmbus dpc] timed out, falling back to bit banging on pin 4
[ 2.991700] fbcon: inteldrmfb (fb0) is primary device
[ 3.027016] [drm:cpt_set_fifo_underrun_reporting] *ERROR* uncleared pch fifo underrun on pch transcoder A
[ 3.027017] [drm:cpt_serr_int_handler] *ERROR* PCH transcoder A FIFO underrun
[ 3.033464] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 3.062197] [drm] Initialized i915 1.6.0 20080730 for 0000:00:02.0 on minor 0
[ 4.314306] [drm] Enabling RC6 states: RC6 on, RC6p on, RC6pp off