我有一个嵌入的plarform，它有两个图形层（/dev/fb0和/dev/fb1）。
我想使用两个独立的过程：
一个直接使用/dev/fb0（raw模式，没有视频库）。
另一个通过directfb使用/dev/fb1。
我可以启动第一个，它运行得很好（我正在使用linux open函数打开/dev/fb0并直接写入它）。
当我尝试启动第二个程序时，它会卡在directfb初始化中。
如果我试图使用/dev/fb1，我不明白为什么directfb会锁定/dev/fb0。
根据@shodanex的请求，下面是第二个进程的strace输出：
[pid 1483] open("/etc/directfbrc", O_RDONLY) = 7
[pid 1483] fstat64(7, {st_mode=S_IFREG|0755, st_size=472, ...}) = 0
[pid 1483] old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2f375000
[pid 1483] read(7, "system=fbdev\n#no-vt\n#no-vt-switc"..., 4096) = 472
[pid 1483] write(2, "(!) DirectFB/Config \'depth\': OK!"..., 39(!) DirectFB/Config 'depth': OK!!!! 32
) = 39
[pid 1483] read(7, "", 4096) = 0
[pid 1483] close(7) = 0
[pid 1483] munmap(0x2f375000, 4096) = 0
[pid 1483] open("/root/.directfbrc", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] write(2, "\n =======================| "..., 270
=======================| DirectFB 1.0.1 |=======================
(c) 2001-2007 The DirectFB Organization (directfb.org)
(c) 2000-2004 Convergence (integrated media) GmbH
------------------------------------------------------------
) = 270
[pid 1483] gettid() = 1483
[pid 1483] rt_sigaction(SIGHUP, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {SIG_DFL}, 8) = 0
[pid 1483] rt_sigaction(SIGINT, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {SIG_DFL}, 8) = 0
[pid 1483] rt_sigaction(SIGTERM, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {SIG_DFL}, 8) = 0
[pid 1483] rt_sigaction(SIGABRT, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {SIG_DFL}, 8) = 0
[pid 1483] rt_sigaction(SIGFPE, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {0x29d6f860, [], 0}, 8) = 0
[pid 1483] rt_sigaction(SIGILL, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {0x29d6f860, [], 0}, 8) = 0
[pid 1483] rt_sigaction(SIGQUIT, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {SIG_DFL}, 8) = 0
[pid 1483] rt_sigaction(SIGSEGV, {0x2a323fc0, [], SA_SIGINFO}, {0x29d6f860, [], 0}, 8) = 0
[pid 1483] rt_sigaction(SIGTRAP, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {SIG_DFL}, 8) = 0
[pid 1483] rt_sigaction(SIGBUS, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {0x29d6f860, [], 0}, 8) = 0
[pid 1483] rt_sigaction(SIGXCPU, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {SIG_DFL}, 8) = 0
[pid 1483] rt_sigaction(SIGXFSZ, {0x2a323fc0, [], SA_NOMASK|SA_SIGINFO}, {SIG_DFL}, 8) = 0
[pid 1483] write(2, "(*) DirectFB/Core: Single Applic"..., 64(*) DirectFB/Core: Single Application Core. (2010-03-25 20:40)
) = 64
[pid 1483] open("/usr/lib/libdirectfb-1.0.so.1", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/lib/directfb-1.0-0/systems", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_DIRECTORY) = 7
[pid 1483] fstat64(7, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
[pid 1483] fcntl64(7, F_SETFD, FD_CLOEXEC) = 0
[pid 1483] getdents(7, /* 10 entries */, 4096) = 288
[pid 1483] open("/usr/lib/directfb-1.0-0/systems/libdirectfb_fbdev.so", O_RDONLY) = 8
[pid 1483] read(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0*\0\1\0\0\0\200&\0\0004\0\0\0"..., 512) = 512
[pid 1483] fstat64(8, {st_mode=S_IFREG|0755, st_size=59543, ...}) = 0
[pid 1483] old_mmap(NULL, 115640, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) = 0x2f378000
[pid 1483] mprotect(0x2f384000, 65536, PROT_NONE) = 0
[pid 1483] old_mmap(0x2f394000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0xc000) = 0x2f394000
[pid 1483] close(8) = 0
[pid 1483] open("/usr/lib/directfb-1.0-0/systems/libdirectfb_x11.so", O_RDONLY) = 8
[pid 1483] read(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0*\0\1\0\0\0\200\35\0\0004\0\0\0"..., 512) = 512
[pid 1483] fstat64(8, {st_mode=S_IFREG|0755, st_size=25273, ...}) = 0
[pid 1483] old_mmap(NULL, 83288, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) = 0x2f398000
[pid 1483] mprotect(0x2f39d000, 61440, PROT_NONE) = 0
[pid 1483] old_mmap(0x2f3ac000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0x4000) = 0x2f3ac000
[pid 1483] close(8) = 0
[pid 1483] open("/usr/local/lib/mylibs/libX11.so.6", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/local/lib/libX11.so.6", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/lib/libX11.so.6", O_RDONLY) = 8
[pid 1483] read(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0*\0\1\0\0\0\340\205\1\0004\0\0\0"..., 512) = 512
[pid 1483] fstat64(8, {st_mode=S_IFREG|0755, st_size=953468, ...}) = 0
[pid 1483] old_mmap(NULL, 895116, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) = 0x2f3b0000
[pid 1483] mprotect(0x2f477000, 65536, PROT_NONE) = 0
[pid 1483] old_mmap(0x2f487000, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0xc7000) = 0x2f487000
[pid 1483] close(8) = 0
[pid 1483] open("/usr/local/lib/mylibs/libXext.so.6", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/local/lib/libXext.so.6", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/lib/libXext.so.6", O_RDONLY) = 8
[pid 1483] read(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0*\0\1\0\0\0\340)\0\0004\0\0\0"..., 512) = 512
[pid 1483] fstat64(8, {st_mode=S_IFREG|0755, st_size=61440, ...}) = 0
[pid 1483] old_mmap(NULL, 114084, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) = 0x2f48c000
[pid 1483] mprotect(0x2f498000, 61440, PROT_NONE) = 0
[pid 1483] old_mmap(0x2f4a7000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0xb000) = 0x2f4a7000
[pid 1483] close(8) = 0
[pid 1483] open("/usr/local/lib/mylibs/libxcb-xlib.so.0", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/local/lib/libxcb-xlib.so.0", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/lib/libxcb-xlib.so.0", O_RDONLY) = 8
[pid 1483] read(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0*\0\1\0\0\0\300\5\0\0004\0\0\0"..., 512) = 512
[pid 1483] fstat64(8, {st_mode=S_IFREG|0755, st_size=5786, ...}) = 0
[pid 1483] old_mmap(NULL, 68112, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) = 0x2f4a8000
[pid 1483] mprotect(0x2f4a9000, 61440, PROT_NONE) = 0
[pid 1483] old_mmap(0x2f4b8000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0) = 0x2f4b8000
[pid 1483] close(8) = 0
[pid 1483] open("/usr/local/lib/mylibs/libxcb.so.1", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/local/lib/libxcb.so.1", O_RDONLY) = -1 ENOENT (No such file or directory)
[pid 1483] open("/usr/lib/libxcb.so.1", O_RDONLY) = 8
[pid 1483] read(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0*\0\1\0\0\0\300u\0\0004\0\0\0"..., 512) = 512
[pid 1483] fstat64(8, {st_mode=S_IFREG|0755, st_size=112671, ...}) = 0
[pid 1483] old_mmap(NULL, 144212, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) = 0x2f4bc000
[pid 1483] mprotect(0x2f4cf000, 65536, PROT_NONE) = 0
[pid 1483] old_mmap(0x2f4df000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0x13000) = 0x2f4df000
[pid 1483] close(8) = 0
[pid 1483] open("/usr/lib/libXau.so.6", O_RDONLY) = 8
[pid 1483] read(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0*\0\1\0\0\0\240\n\0\0004\0\0\0"..., 512) = 512
[pid 1483] fstat64(8, {st_mode=S_IFREG|0755, st_size=10880, ...}) = 0
[pid 1483] old_mmap(NULL, 71644, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) = 0x2f4e0000
[pid 1483] mprotect(0x2f4e2000, 61440, PROT_NONE) = 0
[pid 1483] old_mmap(0x2f4f1000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0x1000) = 0x2f4f1000
[pid 1483] close(8) = 0
[pid 1483] open("/usr/lib/libXdmcp.so.6", O_RDONLY) = 8
[pid 1483] read(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0*\0\1\0\0\0\0\20\0\0004\0\0\0"..., 512) = 512
[pid 1483] fstat64(8, {st_mode=S_IFREG|0755, st_size=23841, ...}) = 0
[pid 1483] old_mmap(NULL, 80376, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 8, 0) = 0x2f4f4000
[pid 1483] mprotect(0x2f4f8000, 61440, PROT_NONE) = 0
[pid 1483] old_mmap(0x2f507000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 8, 0x3000) = 0x2f507000
[pid 1483] close(8) = 0
[pid 1483] getdents(7, /* 0 entries */, 4096) = 0
[pid 1483] close(7) = 0
[pid 1483] munmap(0x2f398000, 83288) = 0
[pid 1483] munmap(0x2f48c000, 114084) = 0
[pid 1483] munmap(0x2f3b0000, 895116) = 0
[pid 1483] munmap(0x2f4a8000, 68112) = 0
[pid 1483] munmap(0x2f4bc000, 144212) = 0
[pid 1483] munmap(0x2f4e0000, 71644) = 0
[pid 1483] munmap(0x2f4f4000, 80376) = 0
[pid 1483] open("/dev/fb1", O_RDWR) = 7
[pid 1483] fcntl64(7, F_SETFD, FD_CLOEXEC) = 0
[pid 1483] setsid() = 1483
[pid 1483] open("/dev/tty0", O_RDONLY|O_NOCTTY) = 8
[pid 1483] ioctl(8, 0x5603, 0x7bbc1d2a) = 0
[pid 1483] ioctl(8, 0x5600, 0x497658) = 0
[pid 1483] ioctl(7, 0x460f, 0x7bbc1d18) = 0
[pid 1483] fstat64(7, {st_mode=S_IFCHR|0600, st_rdev=makedev(29, 1), ...}) = 0
[pid 1483] ioctl(7, 0x4610, 0x7bbc1c28) = 0
[pid 1483] ioctl(8, 0x5606, 0x2) = 0
请注意，directfb读取/etc/directfbrc文件（请提前检查其内容）。
之后什么都不会印。
system=fbdev
fbdev=/dev/fb1
primary-layer=1
no-cursor
bg-color=00000000
disable-module=lirc
disable-module=keyboard
disable-module=ps2mouse
mode=1280x720-60
pixelformat=ARGB
depth=32
hardware
desktop-buffer-mode=backvideo
你知道吗？
他又很生气了。
最佳答案
你能提供更多信息吗：
直接FB在第一个进程未启动时是否工作？
你怎么知道directfb正在锁定/dev/fb0？
linux fb是一个内核驱动程序，您可以使用任何想要使用的用户空间程序，比如directfb
directfb是一个用户空间库，它与linux帧缓冲区一起工作。
所以答案肯定是肯定的，您可以在/dev/fb<x>上使用自己的程序，在/dev/fb0上使用directfb程序。也许你应该strace你的directfb程序来理解为什么它被卡住了。