Lines Matching +full:usb +full:- +full:a +full:- +full:connector
1 .. SPDX-License-Identifier: GPL-2.0
7 Mini-HOWTO for using the earlyprintk=dbgp boot option with a
8 USB2 Debug port key and a debug cable, on x86 systems.
10 You need two computers, the 'USB debug key' special gadget and
11 two USB cables, connected like this::
13 [host/target] <-------> [USB debug key] <-------> [client/console]
18 a) Host/target system needs to have USB debug port capability.
20 You can check this capability by looking at a 'Debug port' bit in
21 the lspci -vvv output::
23 # lspci -vvv
25 …00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03) (p…
27 …Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisIN…
28 …Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- I…
31 Region 0: Memory at fe227000 (32-bit, non-prefetchable) [size=1K]
33 Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
34 Status: D0 PME-Enable- DSel=0 DScale=0 PME+
38 Kernel modules: ehci-hcd
42 If your system does not list a debug port capability then you probably
43 won't be able to use the USB debug key.
45 b) You also need a NetChip USB debug cable/key:
49 This is a small blue plastic connector with two USB connections;
50 it draws power from its USB connections.
52 c) You need a second client/console system with a high speed USB 2.0 port.
55 debug port on the "host/target" system. You cannot use a USB hub in
58 The EHCI debug controller is bound to a specific physical USB
66 usb stack when you plug a usb device into various ports on the
69 Some hardware vendors do not expose the usb debug port with a
70 physical connector and if you find such a device send a complaint
84 a) On the host/target system:
94 /etc/grub.conf. If you are using Grub2 on a BIOS firmware system,
109 regular console is alive - use "earlyprintk=dbgp,keep" to keep
120 get a /dev/ttyUSBx device(s).
124 it up to use /dev/ttyUSB0 - or use a raw 'cat /dev/ttyUSBx' to
128 and find out which port has a debug device connected.
134 kernel messages on the host/target system. You can provoke a harmless
137 echo h > /proc/sysrq-trigger
141 …-9) reBoot Crashdump terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) saK show-bac…
150 If it does not work then please ask about it on the linux-kernel@vger.kernel.org