Hi, On 11/11/15 at 09:32am, Lu, Baolu wrote: > > > 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: Retested it, seems it is not stable. I got a sucessful boot with earlyprintk But only once and there was no "Press Y to continue", I just blindly pressed Y. The other tests failed. Since it is not convinience to test, do you have way to enable the dbc after kernel boot? like echo 1 to a sysfs file to enable it. > > (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. > Most times I have no chance to run minicom before the usb disconnection here. > > 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? > Here is some log on host side. [ 1568.052135] usb 2-2: new SuperSpeed USB device number 5 using xhci_hcd [ 1568.063416] usb 2-2: LPM exit latency is zeroed, disabling LPM. [ 1568.063750] usb 2-2: New USB device found, idVendor=1d6b, idProduct=0004 [ 1568.063751] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1568.063752] usb 2-2: Product: Remote GDB [ 1568.063753] usb 2-2: Manufacturer: Linux [ 1568.063754] usb 2-2: SerialNumber: 0001 [ 1568.065580] usb_debug 2-2:1.0: xhci_dbc converter detected [ 1568.066309] usb 2-2: xhci_dbc converter now attached to ttyUSB0 [ 1580.464706] usb 2-2: USB disconnect, device number 5 [ 1580.464996] xhci_dbc ttyUSB0: xhci_dbc converter now disconnected from ttyUSB0 [ 1580.465062] usb_debug 2-2:1.0: device disconnected [ 1580.670743] usb 2-2: new SuperSpeed USB device number 6 using xhci_hcd [ 1580.682068] usb 2-2: LPM exit latency is zeroed, disabling LPM. [ 1580.682667] usb 2-2: New USB device found, idVendor=1d6b, idProduct=0004 [ 1580.682672] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1580.682675] usb 2-2: Product: Remote GDB [ 1580.682678] usb 2-2: Manufacturer: Linux [ 1580.682681] usb 2-2: SerialNumber: 0001 [ 1580.685190] usb_debug 2-2:1.0: xhci_dbc converter detected [ 1580.687106] usb 2-2: xhci_dbc converter now attached to ttyUSB0 [ 1586.751477] usb 2-2: USB disconnect, device number 6 [ 1586.754248] xhci_dbc ttyUSB0: xhci_dbc converter now disconnected from ttyUSB0 [ 1586.754287] usb_debug 2-2:1.0: device disconnected [ 1586.960399] usb 2-2: new SuperSpeed USB device number 7 using xhci_hcd [ 1586.971562] usb 2-2: LPM exit latency is zeroed, disabling LPM. [ 1586.971916] usb 2-2: New USB device found, idVendor=1d6b, idProduct=0004 [ 1586.971918] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1586.971919] usb 2-2: Product: Remote GDB [ 1586.971921] usb 2-2: Manufacturer: Linux [ 1586.971922] usb 2-2: SerialNumber: 0001 [ 1586.973140] usb_debug 2-2:1.0: xhci_dbc converter detected [ 1586.973939] usb 2-2: xhci_dbc converter now attached to ttyUSB0 [ 1616.615418] usb 2-2: USB disconnect, device number 7 [ 1616.617865] xhci_dbc ttyUSB0: xhci_dbc converter now disconnected from ttyUSB0 [ 1616.617918] usb_debug 2-2:1.0: device disconnected [ 1616.823351] usb 2-2: new SuperSpeed USB device number 8 using xhci_hcd [ 1616.834520] usb 2-2: LPM exit latency is zeroed, disabling LPM. [ 1616.834856] usb 2-2: New USB device found, idVendor=1d6b, idProduct=0004 [ 1616.834858] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1616.834859] usb 2-2: Product: Remote GDB [ 1616.834860] usb 2-2: Manufacturer: Linux [ 1616.834860] usb 2-2: SerialNumber: 0001 [ 1616.836715] usb_debug 2-2:1.0: xhci_dbc converter detected [ 1616.837327] usb 2-2: xhci_dbc converter now attached to ttyUSB0 [ 1622.719311] usb 2-2: USB disconnect, device number 8 [ 1622.721962] xhci_dbc ttyUSB0: xhci_dbc converter now disconnected from ttyUSB0 [ 1622.721995] usb_debug 2-2:1.0: device disconnected [ 1622.928226] usb 2-2: new SuperSpeed USB device number 9 using xhci_hcd [ 1622.939383] usb 2-2: LPM exit latency is zeroed, disabling LPM. [ 1622.939714] usb 2-2: New USB device found, idVendor=1d6b, idProduct=0004 [ 1622.939715] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1622.939716] usb 2-2: Product: Remote GDB [ 1622.939717] usb 2-2: Manufacturer: Linux [ 1622.939718] usb 2-2: SerialNumber: 0001 [ 1622.941593] usb_debug 2-2:1.0: xhci_dbc converter detected [ 1622.942187] usb 2-2: xhci_dbc converter now attached to ttyUSB0 [ 1631.312112] usb 2-2: USB disconnect, device number 9 [ 1631.315427] xhci_dbc ttyUSB0: xhci_dbc converter now disconnected from ttyUSB0 [ 1631.315465] usb_debug 2-2:1.0: device disconnected [ 1631.521007] usb 2-2: new SuperSpeed USB device number 10 using xhci_hcd [ 1631.532212] usb 2-2: LPM exit latency is zeroed, disabling LPM. [ 1631.532544] usb 2-2: New USB device found, idVendor=1d6b, idProduct=0004 [ 1631.532545] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1631.532546] usb 2-2: Product: Remote GDB [ 1631.532547] usb 2-2: Manufacturer: Linux [ 1631.532548] usb 2-2: SerialNumber: 0001 [ 1631.534413] usb_debug 2-2:1.0: xhci_dbc converter detected [ 1631.535117] usb 2-2: xhci_dbc converter now attached to ttyUSB0 [ 1633.252488] usb 2-2: USB disconnect, device number 10 [ 1633.255279] xhci_dbc ttyUSB0: xhci_dbc converter now disconnected from ttyUSB0 [ 1633.255314] usb_debug 2-2:1.0: device disconnected [ 1633.461411] usb 2-2: new SuperSpeed USB device number 11 using xhci_hcd [ 1633.472598] usb 2-2: LPM exit latency is zeroed, disabling LPM. [ 1633.472932] usb 2-2: New USB device found, idVendor=1d6b, idProduct=0004 [ 1633.472933] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1633.472934] usb 2-2: Product: Remote GDB [ 1633.472935] usb 2-2: Manufacturer: Linux [ 1633.472936] usb 2-2: SerialNumber: 0001 [ 1633.473987] usb_debug 2-2:1.0: xhci_dbc converter detected [ 1633.474624] usb 2-2: xhci_dbc converter now attached to ttyUSB0 [ 1633.900927] usb 2-2: USB disconnect, device number 11 [ 1633.901176] xhci_dbc ttyUSB0: xhci_dbc converter now disconnected from ttyUSB0 [ 1633.901226] usb_debug 2-2:1.0: device disconnected [ 1634.106831] usb 2-2: new SuperSpeed USB device number 12 using xhci_hcd [ 1634.117987] usb 2-2: LPM exit latency is zeroed, disabling LPM. [ 1634.118328] usb 2-2: New USB device found, idVendor=1d6b, idProduct=0004 [ 1634.118329] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 1634.118330] usb 2-2: Product: Remote GDB [ 1634.118331] usb 2-2: Manufacturer: Linux [ 1634.118332] usb 2-2: SerialNumber: 0001 [ 1634.120194] usb_debug 2-2:1.0: xhci_dbc converter detected [ 1634.120949] usb 2-2: xhci_dbc converter now attached to ttyUSB0 Thanks Dave -- 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
