On Tue, Mar 3, 2009 at 3:53 PM, Sarah Sharp <sarah.a.sharp@xxxxxxxxx> wrote: > Greetings, > > You wrote the EHCI debug port patch for early printk back in July 2008 > (commit 5c05917e7fe313a187ad6ebb94c1c6cf42862a0b). Can you add some > documentation to the Documentation directory about how a Linux user > would set up a system (cables, files to open to get the printks, etc.)? please check ========================================================================================== USB Debug port using Howto 1. HW: a. target system need to have debug port 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 Kernel driver in use: ehci_hcd Kernel modules: ehci-hcd 00: 86 80 36 28 06 01 90 02 03 20 03 0c 00 00 00 00 10: 00 70 22 fe 00 00 00 00 00 00 00 00 00 00 00 00 20: 00 00 00 00 00 00 00 00 00 00 00 00 aa 17 ab 20 30: 00 00 00 00 50 00 00 00 00 00 00 00 0b 04 00 00 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 50: 01 58 c2 c9 00 80 00 00 0a 00 a0 20 00 00 00 00 60: 20 20 9f 01 00 00 00 00 01 00 00 01 00 00 08 80 70: c0 00 17 3f 00 00 00 00 00 00 00 00 00 00 00 00 80: 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 d0: 00 00 00 00 00 aa ff 00 00 00 00 00 00 00 00 00 e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f0: 00 00 00 00 88 85 40 00 86 0f 05 00 06 17 02 20 b. netchip USB debug cable c. console system: have USB port 2. SW setting a. console system: need to have kernel config CONFIG_USB_SERIAL_DEBUG you should get /dev/ttyUSBx # cat /dev/ttyUSBx could get output b. target system: need to have kernel config CONFIG_EARLY_PRINTK_DBGP boot command line: earlyprintk=dbgp c. for Nvidia Southbridge based system: kernel will try to probe and find out which port has debug device connected. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html