after running command "xinit &" to start X window, system should display X window on the monitor automatically. notes: 1. not all BDW machine can reproduce this issue. 2. if this issue arise, even uses older kernel and older X11R7, it also can be reproduced. (for example: kernel:20140227_nightly and X11R7:20140227_stable) 1. Testing Env: ======================================================================== kernel: 3.15.0-rc5_drm-intel-fixes_4ba480_20140521 X11R7: X11R7.stable.2014-05-20.tar.gz 2. Testing Steps: ======================================================================== 1.boot up system 2.running cmd "xinit &" to start X window 3.check the the monitor, the X windows cannot display workround: 1.after running "xinit &", run command "ps aux |grep X" to check which tty are using by X(for example:tty2 ) 2.run command "chvt 2" 3.check the the monitor, the X windows can display now. 3. Debug Information: (gdb) bt #0 0x000000372f0ebfb7 in ioctl () from /usr/lib64/libc.so.6 #1 0x00000000004b4a99 in switch_to (vt=2, from=from@entry=0x5c07b1 "xf86OpenConsole") at lnx_init.c:74 #2 0x00000000004b4e60 in xf86OpenConsole () at lnx_init.c:197 #3 0x0000000000490a9f in InitOutput ( pScreenInfo=pScreenInfo@entry=0x82a880 <screenInfo>, argc=argc@entry=2, argv=argv@entry=0x7fffca1e40e8) at xf86Init.c:552 #4 0x000000000043cf0d in dix_main (argc=2, argv=<optimized out>, envp=<optimized out>) at main.c:200 #5 0x000000372f021b75 in __libc_start_main () from /usr/lib64/libc.so.6 #6 0x00000000004277e1 in _start () 3. Frequency of Occurence: ======================================================================== machine 1：Test 5 times, and this issue arise 4 times. machine 2：cannot reproduce this issue.
It's a nasty bug. diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c index 2bd78e2ac8ec..a7bdc4b21b49 100644 --- a/drivers/tty/vt/vt_ioctl.c +++ b/drivers/tty/vt/vt_ioctl.c @@ -684,7 +684,8 @@ int vt_ioctl(struct tty_struct *tty, console_unlock(); if (ret) break; - set_console(arg); + if (set_console(arg)) + ret = -EIO; } break; Turns the indefinite hang into a detectable error (and prevents X from starting) when the bug occurs. This needs to be sent upstream. Greg Kroah-Hartman <gregkh@linuxfoundation.org> Jiri Slaby <jslaby@suse.cz> linux-kernel@vger.kernel.org and bugzilla.kernel.org
seem this patch doesn't work, verify this issue with following kernel and X11R7 kernel: the latest drm-intel-nightly(f5b0c......12be4) + Chris Wilson's patch X11R7: X11R7.stable.2014-05-21.tar.gz it also can be reproduced.
cannot reproduce it now, so close it. if it arise again, i will reopen it.
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