从原来的fedora5，换为安装fedora7 之后，minicom的使用还有点曲折。最开始说没有default 设置，我就minicom -s建立了一个df1，配置好了我需要的配置，退出，重新进入minicom，居然没有什么反应，至此，我就不停的换/dev/tty0, /dev/ttyS0 , /dev/modem , 建立ln -fs /dev/ttyS0 /dev/modem. 还是不行，真是很奇怪，因为在fedora下面没有什么曲折，一敲minicom ，轻松配置后就可以用了，这是怎么回事？
我再试试看usb转串口，很容易的就可以了。算了，放一放吧。经过了一个周末，今天来，试试看我的minicom df1. 连上我的设备，居然可以了。我的天。原来配置完毕后要重启。
至此，我的fedora7 下面就可以使用串口ttyS0了。
事情没有这么简单，又重新启动了一次，minicom（用ttyS0）又不行了，想想这两次的区别是我fedora7的启动选项不一样，可以用的那次我启动的是xxxbasexxx的那项，不行的这次启动的是xxx xen xxx的那项，这肯定跟xen有关系，上网去查查，果然，我看到了这一篇文章《FC6 中串口不能正常使用的原因与解决办法》。
新安装了个FC6，用来调我的SIGMAL 8260的板子，由于对XEN感兴趣，索兴在安装FC6时就将XEN选上了，装完后，感觉不错，但是当用串口时就发现不能正常使用，因为我的PC只有一个串口出来，即ttyS0，可以用minicom正常打开，但就是不能工作，后来想想可能是XEN的配置有问题，我就又编了一个新的KERNEL，然后改了改GRUB，新的内核不在XEN上跑，串口正常工作。
其实，FC6以XEN的方式安装时，GRUB中就已经为你做了一个不能XEN的跑的选项，你只要修改一下grub.conf文件，将hiddenmenu 关掉即可。
如果非要在XEN下用串口也可以，默认情况XEN用了ttyS0,你可以用dmesg|grep ttyS0 可以看到
kernel: Xen virtual console successfully installed as ttyS0
这个提示，说明XEN占用了ttyS0, 这时你只要修改xen的启动参数，在grub.conf中，如下
xencons=off.
module /boot/vmlinuz-2.6-xen ro root=/dev/sda1 xencons=ttyS9
重新reboot，后进入linux就可测试一下你的ttyS0是不是可以用了。如果不能用，那你就要查查你的是不是装上了串口驱动了！
通过dmesg命令，查看我的信息：
[anna@localhost dev]$ dmesg
Linux version 2.6.20-2925.11.fc7xen (kojibuilder@hammer2.fedora.redhat.com) (gcc version 4.1.2 20070502 (Red Hat 4.1.2-12)) #1 SMP Mon Jun 11 16:21:08 EDT 2007
BIOS-provided physical RAM map:
sanitize start
sanitize bail 0
copy_e820_map() start: 0000000000000000 size: 000000001d801000 end: 000000001d801000 type: 1
Xen: 0000000000000000 - 000000001d801000 (usable)
0MB HIGHMEM available.
472MB LOWMEM available.
Using x86 segment limits to approximate NX protection
Entering add_active_range(0, 0, 120833) 0 entries of 256 used
Zone PFN ranges:
DMA 0 -> 120833
Normal 120833 -> 120833
HighMem 120833 -> 120833
early_node_map[1] active PFN ranges
0: 0 -> 120833
On node 0 totalpages: 120833
DMA zone: 944 pages used for memmap
DMA zone: 0 pages reserved
DMA zone: 119889 pages, LIFO batch:31
Normal zone: 0 pages used for memmap
HighMem zone: 0 pages used for memmap
found SMP MP-table at 000fb960
DMI 2.3 present.
ACPI: RSDP (v000 AMI ) @ 0x000fa0b0
ACPI: RSDT (v001 AMIINT INTEL845 0x00000010 MSFT 0x00000097) @ 0x1fff0000
ACPI: FADT (v001 AMIINT INTEL845 0x00000011 MSFT 0x00000097) @ 0x1fff0030
ACPI: MADT (v001 AMIINT INTEL845 0x00000009 MSFT 0x00000097) @ 0x1fff00c0
ACPI: DSDT (v001 INTEL BROKDLEG 0x00001000 MSFT 0x0100000d) @ 0x00000000
ACPI: Local APIC address 0xfee00000
ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
ACPI: LAPIC (acpi_id[0x02] lapic_id[0x01] disabled)
ACPI: IOAPIC (id[0x02] address[0xfec00000] gsi_base[0])
IOAPIC[0]: apic_id 2, version 32, address 0xfec00000, GSI 0-23
ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl)
ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level)
ACPI: IRQ0 used by override.
ACPI: IRQ2 used by override.
ACPI: IRQ9 used by override.
Enabling APIC mode: Flat. Using 1 I/O APICs
Using ACPI (MADT) for SMP configuration information
Built 1 zonelists. Total pages: 119889
Kernel command line: ro root=LABEL=/ rhgb quiet
Enabling fast FPU save and restore... done.
Enabling unmasked SIMD FPU exception support... done.
Initializing CPU#0
CPU 0 irqstacks, hard=c135c000 soft=c133c000
PID hash table entries: 2048 (order: 11, 8192 bytes)
Xen reported: 1992.693 MHz processor.
Console: colour VGA+ 80x50
Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
... MAX_LOCKDEP_SUBCLASSES: 8
... MAX_LOCK_DEPTH: 30
... MAX_LOCKDEP_KEYS: 2048
... CLASSHASH_SIZE: 1024
... MAX_LOCKDEP_ENTRIES: 8192
... MAX_LOCKDEP_CHAINS: 16384
... CHAINHASH_SIZE: 8192
memory used by lock dependency info: 1064 kB
per task-struct memory footprint: 1200 bytes
Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
Software IO TLB enabled:
Aperture: 2 megabytes
Kernel range: 0x00000000c015f000 - 0x00000000c035f000
Address size: 30 bits
vmalloc area: de800000-f4ffe000, maxmem 2d7fe000
Memory: 453760k/483332k available (2022k kernel code, 21136k reserved, 1075k data, 180k init, 0k highmem)
virtual kernel memory layout:
fixmap : 0xf5315000 - 0xf57fe000 (5028 kB)
pkmap : 0xf5000000 - 0xf5200000 (2048 kB)
vmalloc : 0xde800000 - 0xf4ffe000 ( 359 MB)
lowmem : 0xc0000000 - 0xdd801000 ( 472 MB)
.init : 0xc130b000 - 0xc1338000 ( 180 kB)
.data : 0xc11f9a5d - 0xc1306714 (1075 kB)
.text : 0xc1000000 - 0xc11f9a5d (2022 kB)
Checking if this processor honours the WP bit even in supervisor mode... Ok.
Calibrating delay using timer specific routine.. 4986.97 BogoMIPS (lpj=9973949)
Security Framework v1.0.0 initialized
SELinux: Initializing.
SELinux: Starting in permissive mode
selinux_register_security: Registering secondary module capability
Capability LSM initialized as secondary
Mount-cache hash table entries: 512
CPU: After generic identify, caps: 3febd3f1 00000000 00000000 00000000 00000000 00000000 00000000
CPU: Trace cache: 12K uops, L1 D cache: 8K
CPU: L2 cache: 512K
CPU: After all inits, caps: 3febd3f1 00000000 00000000 00003080 00000000 00000000 00000000
Checking 'hlt' instruction... OK.
SMP alternatives: switching to UP code
Freeing SMP alternatives: 11k freed
ACPI: Core revision 20060707
ENABLING IO-APIC IRQs
Brought up 1 CPUs
sizeof(vma)=88 bytes
sizeof(page)=32 bytes
sizeof(inode)=564 bytes
sizeof(dentry)=156 bytes
sizeof(ext3inode)=800 bytes
sizeof(buffer_head)=56 bytes
sizeof(skbuff)=176 bytes
sizeof(task_struct)=2656 bytes
Grant table initialized
NET: Registered protocol family 16
ACPI: bus type pci registered
PCI: Using configuration type 1
Setting up standard PCI resources
Allocating PCI resources starting at 30000000 (gap: 20000000:dec00000)
ACPI: Interpreter enabled
ACPI: Using IOAPIC for interrupt routing
ACPI: PCI Root Bridge [PCI0] (0000:00)
PCI: Probing PCI hardware (bus 00)
PCI quirk: region 0800-087f claimed by ICH4 ACPI/GPIO/TCO
PCI quirk: region 0400-043f claimed by ICH4 GPIO
Boot video device is 0000:01:00.0
PCI: Transparent bridge - 0000:00:1e.0
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT]
ACPI: PCI Interrupt Routing Table [\_SB_.PCI0.ICHB._PRT]
ACPI: Power Resource [URP1] (off)
ACPI: Power Resource [URP2] (off)
ACPI: Power Resource [FDDP] (off)
ACPI: Power Resource [LPTP] (off)
ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 6 7 10 *11 12 14 15)
ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 6 7 10 *11 12 14 15)
ACPI: PCI Interrupt Link [LNKC] (IRQs 3 4 5 6 7 10 11 *12 14 15)
ACPI: PCI Interrupt Link [LNKD] (IRQs 3 4 *5 6 7 10 11 12 14 15)
ACPI: PCI Interrupt Link [LNKE] (IRQs 3 4 5 6 7 10 11 12 14 15) *0, disabled.
ACPI: PCI Interrupt Link [LNKF] (IRQs 3 4 5 6 7 *10 11 12 14 15)
ACPI: PCI Interrupt Link [LNKG] (IRQs 3 4 *5 6 7 10 11 12 14 15)
ACPI: PCI Interrupt Link [LNKH] (IRQs 3 4 5 6 7 *10 11 12 14 15)
Linux Plug and Play Support v0.97 (c) Adam Belay
pnp: PnP ACPI init
pnp: PnP ACPI: found 9 devices
xen_mem: Initialising balloon driver.
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
PCI: Using ACPI for IRQ routing
PCI: If a device doesn't work, try "pci=routeirq". If it helps, post a report
NetLabel: Initializing
NetLabel: domain hash size = 128
NetLabel: protocols = UNLABELED CIPSOv4
NetLabel: unlabeled traffic allowed by default
PCI: Bridge: 0000:00:01.0
IO window: disabled.
MEM window: ddd00000-dfdfffff
PREFETCH window: cdc00000-ddbfffff
PCI: Bridge: 0000:00:1e.0
IO window: c000-cfff
MEM window: dfe00000-dfefffff
PREFETCH window: 30000000-300fffff
PCI: Setting latency timer of device 0000:00:1e.0 to 64
NET: Registered protocol family 2
IP route cache hash table entries: 4096 (order: 2, 16384 bytes)
TCP established hash table entries: 16384 (order: 7, 524288 bytes)
TCP bind hash table entries: 8192 (order: 6, 262144 bytes)
TCP: Hash tables configured (established 16384 bind 8192)
TCP reno registered
checking if image is initramfs... it is
Freeing initrd memory: 7181k freed
IA-32 Microcode Update Driver: v1.14-xen <tigran@veritas.com>
audit: initializing netlink socket (disabled)
audit(1186397539.088:1): initialized
VFS: Disk quotas dquot_6.5.1
Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
SELinux: Registering netfilter hooks
io scheduler noop registered
io scheduler anticipatory registered
io scheduler deadline registered
io scheduler cfq registered (default)
pci_hotplug: PCI Hot Plug PCI Core version: 0.5
ACPI: Processor [CPU1] (supports 8 throttling states)
ACPI Exception (acpi_processor-0677): AE_NOT_FOUND, Processor Device is not present [20060707]
Real Time Clock Driver v1.12ac
Non-volatile memory driver v1.2
Linux agpgart interface v0.101 (c) Dave Jones
agpgart: Detected an Intel i845 Chipset.
agpgart: AGP aperture is 64M @ 0xe0000000
RAMDISK driver initialized: 16 RAM disks of 16384K size 4096 blocksize
input: Macintosh mouse button emulation as /class/input/input0
Xen virtual console successfully installed as ttyS0
Event-channel device installed.
usbcore: registered new interface driver libusual
usbcore: registered new interface driver hiddev
usbcore: registered new interface driver usbhid
drivers/usb/input/hid-core.c: v2.6:USB HID core driver
...
在以上信息里面发现了这句话，“Xen virtual console successfully installed as ttyS0”，果然，ttyS0被占用了。
