Messages in this thread | | | Subject | Re: [PATCH v3 00/12] usb: early: add support for early printk through USB3 debug port | From | "Lu, Baolu" <> | Date | Wed, 11 Nov 2015 09:32:47 +0800 |
| |
On 11/10/2015 05:39 PM, Dave Young wrote: > Hi, > > On 11/09/15 at 03:38pm, Lu Baolu wrote: >> This patch series adds support for early printk through USB3 debug port. >> USB3 debug port is described in xHCI specification as an optional extended >> capability. >> > I did a test with your previous patchset with the manually wired cable. > debug host detected the remote device, but later the devie automaticlly > disconnected and earlyprintk hangs.
Hi Dave,
What I have done is:
(1) Build a new kernel for debug target with this patch series applied. (2) Add "earlyprintk=xdbc" to the kernel option of debug target. The "keep" option for early printk doesn't support yet. (That's my next target.)
(3) Boot the debug host, and disable USB runtime suspend:
# echo on > /sys/bus/pci/devices/<xhci_pci_bus_name>/power/control # echo on | tee /sys/bus/usb/devices/*/power/control
(4) Boot the debug target. Check the dmesg message on debug host.
# tail -f /var/log/kern.log
Nov 12 01:27:50 allen-ult kernel: [ 1815.983374] usb 4-3: new SuperSpeed USB device number 4 using xhci_hcd Nov 12 01:27:50 allen-ult kernel: [ 1815.999595] usb 4-3: LPM exit latency is zeroed, disabling LPM. Nov 12 01:27:50 allen-ult kernel: [ 1815.999899] usb 4-3: New USB device found, idVendor=1d6b, idProduct=0004 Nov 12 01:27:50 allen-ult kernel: [ 1815.999902] usb 4-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3 Nov 12 01:27:50 allen-ult kernel: [ 1815.999903] usb 4-3: Product: Remote GDB Nov 12 01:27:50 allen-ult kernel: [ 1815.999904] usb 4-3: Manufacturer: Linux Nov 12 01:27:50 allen-ult kernel: [ 1815.999905] usb 4-3: SerialNumber: 0001 Nov 12 01:27:50 allen-ult kernel: [ 1816.000240] usb_debug 4-3:1.0: xhci_dbc converter detected Nov 12 01:27:50 allen-ult kernel: [ 1816.000360] usb 4-3: xhci_dbc converter now attached to ttyUSB0
(5) Host has completed enumeration of debug device. Start "minicom" on debug host.
Welcome to minicom 2.7
OPTIONS: I18n Compiled on Jan 1 2014, 17:13:19. Port /dev/ttyUSB0, 01:28:02
Press CTRL-A Z for help on special keys
Press Y to continue...
(6) You should be able to see "Press Y to continue..." (if not, try pressing Enter key) Press Y key, debug target should go ahead with boot and early boot messages should show in mincom.
Press Y to continue... [ 0.000000] Initializing cgroup subsys cpuset [ 0.000000] Initializing cgroup subsys cpu [ 0.000000] Initializing cgroup subsys cpuacct [ 0.000000] Linux version 4.3.0-rc7+ (allen@blu-skl) (gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04) 5 [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.3.0-rc7+ root=UUID=5a2fb856-0238-4b6e-aa45-beeccb7 [ 0.000000] KERNEL supported cpus:
[...skipped...]
[ 0.000000] Offload RCU callbacks from CPUs: 0-7. [ 0.000000] Console: colour dummy device 80x25 [ 0.000000] console [tty0] enabled [ 0.000000] bootconsole [earlyxdbc0] disabled
So "the devie automaticlly disconnected and earlyprintk hangs" happens in which step?
Thanks, Baolu
> > I have not got more time, will try your new patchset when I have time. > > Thanks > Dave >
| |