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Merge branch 'x86-stage-3-for-linus' of git://git.kernel.org/pub/scm/…
…linux/kernel/git/tip/linux-2.6-tip * 'x86-stage-3-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (190 commits) Revert "cpuacct: reduce one NULL check in fast-path" Revert "x86: don't compile vsmp_64 for 32bit" x86: Correct behaviour of irq affinity x86: early_ioremap_init(), use __fix_to_virt(), because we are sure it's safe x86: use default_cpu_mask_to_apicid for 64bit x86: fix set_extra_move_desc calling x86, PAT, PCI: Change vma prot in pci_mmap to reflect inherited prot x86/dmi: fix dmi_alloc() section mismatches x86: e820 fix various signedness issues in setup.c and e820.c x86: apic/io_apic.c define msi_ir_chip and ir_ioapic_chip all the time x86: irq.c keep CONFIG_X86_LOCAL_APIC interrupts together x86: irq.c use same path for show_interrupts x86: cpu/cpu.h cleanup x86: Fix a couple of sparse warnings in arch/x86/kernel/apic/io_apic.c Revert "x86: create a non-zero sized bm_pte only when needed" x86: pci-nommu.c cleanup x86: io_delay.c cleanup x86: rtc.c cleanup x86: i8253 cleanup x86: kdebugfs.c cleanup ...
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Mini-HOWTO for using the earlyprintk=dbgp boot option with a | ||
USB2 Debug port key and a debug cable, on x86 systems. | ||
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You need two computers, the 'USB debug key' special gadget and | ||
and two USB cables, connected like this: | ||
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[host/target] <-------> [USB debug key] <-------> [client/console] | ||
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1. There are three specific hardware requirements: | ||
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a.) Host/target system needs to have USB debug port capability. | ||
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You can check this capability by looking at a 'Debug port' bit in | ||
the lspci -vvv output: | ||
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# lspci -vvv | ||
... | ||
00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03) (prog-if 20 [EHCI]) | ||
Subsystem: Lenovo ThinkPad T61 | ||
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx- | ||
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- | ||
Latency: 0 | ||
Interrupt: pin D routed to IRQ 19 | ||
Region 0: Memory at fe227000 (32-bit, non-prefetchable) [size=1K] | ||
Capabilities: [50] Power Management version 2 | ||
Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold+) | ||
Status: D0 PME-Enable- DSel=0 DScale=0 PME+ | ||
Capabilities: [58] Debug port: BAR=1 offset=00a0 | ||
^^^^^^^^^^^ <==================== [ HERE ] | ||
Kernel driver in use: ehci_hcd | ||
Kernel modules: ehci-hcd | ||
... | ||
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( If your system does not list a debug port capability then you probably | ||
wont be able to use the USB debug key. ) | ||
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b.) You also need a Netchip USB debug cable/key: | ||
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http://www.plxtech.com/products/NET2000/NET20DC/default.asp | ||
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This is a small blue plastic connector with two USB connections, | ||
it draws power from its USB connections. | ||
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c.) Thirdly, you need a second client/console system with a regular USB port. | ||
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2. Software requirements: | ||
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a.) On the host/target system: | ||
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You need to enable the following kernel config option: | ||
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CONFIG_EARLY_PRINTK_DBGP=y | ||
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And you need to add the boot command line: "earlyprintk=dbgp". | ||
(If you are using Grub, append it to the 'kernel' line in | ||
/etc/grub.conf) | ||
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NOTE: normally earlyprintk console gets turned off once the | ||
regular console is alive - use "earlyprintk=dbgp,keep" to keep | ||
this channel open beyond early bootup. This can be useful for | ||
debugging crashes under Xorg, etc. | ||
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b.) On the client/console system: | ||
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You should enable the following kernel config option: | ||
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CONFIG_USB_SERIAL_DEBUG=y | ||
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On the next bootup with the modified kernel you should | ||
get a /dev/ttyUSBx device(s). | ||
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Now this channel of kernel messages is ready to be used: start | ||
your favorite terminal emulator (minicom, etc.) and set | ||
it up to use /dev/ttyUSB0 - or use a raw 'cat /dev/ttyUSBx' to | ||
see the raw output. | ||
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c.) On Nvidia Southbridge based systems: the kernel will try to probe | ||
and find out which port has debug device connected. | ||
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3. Testing that it works fine: | ||
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You can test the output by using earlyprintk=dbgp,keep and provoking | ||
kernel messages on the host/target system. You can provoke a harmless | ||
kernel message by for example doing: | ||
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echo h > /proc/sysrq-trigger | ||
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On the host/target system you should see this help line in "dmesg" output: | ||
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SysRq : HELP : loglevel(0-9) reBoot Crashdump terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) saK show-backtrace-all-active-cpus(L) show-memory-usage(M) nice-all-RT-tasks(N) powerOff show-registers(P) show-all-timers(Q) unRaw Sync show-task-states(T) Unmount show-blocked-tasks(W) dump-ftrace-buffer(Z) | ||
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On the client/console system do: | ||
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cat /dev/ttyUSB0 | ||
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And you should see the help line above displayed shortly after you've | ||
provoked it on the host system. | ||
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If it does not work then please ask about it on the linux-kernel@vger.kernel.org | ||
mailing list or contact the x86 maintainers. |
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