Hi, If I add "earlycon" to the kernel parameter, the log message on the earlycon is also displayed to the regular console. In other words, the same log messages are displayed twice. I noticed this problem on v4.4-rc1. It has not been fixed in the mainline yet, I think. Anybody who has a clue? (I have not done git-bisect yet.) I attached my log below: [ 0.000000] Booting Linux on physical CPU 0x0 [ 0.000000] Linux version 4.4.0-rc1-00003-gc590deb-dirty (yamada@beagle) (gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-12ubuntu1) ) #249 SMP Fri Nov 27 19:09:26 JST 2015 [ 0.000000] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=10c5387d [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache [ 0.000000] Machine model: UniPhier PH1-LD4 Reference Board [ 0.000000] bootconsole [uart0] enabled [ 0.000000] cma: Reserved 64 MiB at 0x9b800000 [ 0.000000] Memory policy: Data cache writeback [ 0.000000] CPU: All CPU(s) started in SVC mode. [ 0.000000] PERCPU: Embedded 12 pages/cpu @dfbc5000 s19136 r8192 d21824 u49152 [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 130048 [ 0.000000] Kernel command line: earlycon [ 0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes) [ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes) [ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes) [ 0.000000] Memory: 436816K/524288K available (8235K kernel code, 1040K rwdata, 3816K rodata, 1048K init, 340K bss, 21936K reserved, 65536K cma-reserved, 0K highmem) [ 0.000000] Virtual kernel memory layout: [ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB) [ 0.000000] fixmap : 0xffc00000 - 0xfff00000 (3072 kB) [ 0.000000] vmalloc : 0xe0800000 - 0xff800000 ( 496 MB) [ 0.000000] lowmem : 0xc0000000 - 0xe0000000 ( 512 MB) [ 0.000000] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB) [ 0.000000] modules : 0xbf000000 - 0xbfe00000 ( 14 MB) [ 0.000000] .text : 0xc0208000 - 0xc0dcdc40 (12056 kB) [ 0.000000] .init : 0xc0dce000 - 0xc0ed4000 (1048 kB) [ 0.000000] .data : 0xc0ed4000 - 0xc0fd82e0 (1041 kB) [ 0.000000] .bss : 0xc0fdb000 - 0xc10303e8 ( 341 kB) [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1 [ 0.000000] Hierarchical RCU implementation. [ 0.000000] Build-time adjustment of leaf fanout to 32. [ 0.000000] RCU restricting CPUs from NR_CPUS=16 to nr_cpu_ids=1. [ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=32, nr_cpu_ids=1 [ 0.000000] NR_IRQS:16 nr_irqs:16 16 [ 0.000000] uniphier: enabled outer cache (cache level: 2) [ 0.000009] sched_clock: 64 bits at 50MHz, resolution 20ns, wraps every 4398046511100ns [ 0.007999] clocksource: arm_global_timer: mask: 0xffffffffffffffff max_cycles: 0xb8812736b, max_idle_ns: 440795202655 ns [ 0.019168] Console: colour dummy device 80x30 [ 0.023602] console [tty0] enabled [ 0.027030] bootconsole [uart0] disabled [ 0.000000] Booting Linux on physical CPU 0x0 [ 0.000000] Linux version 4.4.0-rc1-00003-gc590deb-dirty (yamada@beagle) (gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-12ubuntu1) ) #249 SMP Fri Nov 27 19:09:26 JST 2015 [ 0.000000] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=10c5387d [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache [ 0.000000] Machine model: UniPhier PH1-LD4 Reference Board [ 0.000000] bootconsole [uart0] enabled [ 0.000000] cma: Reserved 64 MiB at 0x9b800000 [ 0.000000] Memory policy: Data cache writeback [ 0.000000] CPU: All CPU(s) started in SVC mode. [ 0.000000] PERCPU: Embedded 12 pages/cpu @dfbc5000 s19136 r8192 d21824 u49152 [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 130048 [ 0.000000] Kernel command line: earlycon [ 0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes) [ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes) [ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes) [ 0.000000] Memory: 436816K/524288K available (8235K kernel code, 1040K rwdata, 3816K rodata, 1048K init, 340K bss, 21936K reserved, 65536K cma-reserved, 0K highmem) [ 0.000000] Virtual kernel memory layout: [ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB) [ 0.000000] fixmap : 0xffc00000 - 0xfff00000 (3072 kB) [ 0.000000] vmalloc : 0xe0800000 - 0xff800000 ( 496 MB) [ 0.000000] lowmem : 0xc0000000 - 0xe0000000 ( 512 MB) [ 0.000000] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB) [ 0.000000] modules : 0xbf000000 - 0xbfe00000 ( 14 MB) [ 0.000000] .text : 0xc0208000 - 0xc0dcdc40 (12056 kB) [ 0.000000] .init : 0xc0dce000 - 0xc0ed4000 (1048 kB) [ 0.000000] .data : 0xc0ed4000 - 0xc0fd82e0 (1041 kB) [ 0.000000] .bss : 0xc0fdb000 - 0xc10303e8 ( 341 kB) [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1 [ 0.000000] Hierarchical RCU implementation. [ 0.000000] Build-time adjustment of leaf fanout to 32. [ 0.000000] RCU restricting CPUs from NR_CPUS=16 to nr_cpu_ids=1. [ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=32, nr_cpu_ids=1 [ 0.000000] NR_IRQS:16 nr_irqs:16 16 [ 0.000000] uniphier: enabled outer cache (cache level: 2) [ 0.000009] sched_clock: 64 bits at 50MHz, resolution 20ns, wraps every 4398046511100ns [ 0.007999] clocksource: arm_global_timer: mask: 0xffffffffffffffff max_cycles: 0xb8812736b, max_idle_ns: 440795202655 ns [ 0.019168] Console: colour dummy device 80x30 [ 0.023602] console [tty0] enabled [ 0.027030] bootconsole [uart0] disabled [ 0.030963] Calibrating delay loop... 1590.88 BogoMIPS (lpj=3977216) [ 0.049045] pid_max: default: 32768 minimum: 301 [ 0.049161] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes) [ 0.049178] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes) [ 0.049891] CPU: Testing write buffer coherency: ok [ 0.050097] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000 [ 0.050180] Setting up static identity map for 0x80209000 - 0x80209098 [ 0.051503] Brought up 1 CPUs [ 0.051520] SMP: Total of 1 processors activated (1590.88 BogoMIPS). [ 0.051533] CPU: All CPU(s) started in SVC mode. [ 0.052170] devtmpfs: initialized [ 0.053754] VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 4 [ 0.054146] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 9556302231375000 ns [ 0.057309] pinctrl core: initialized pinctrl subsystem [ 0.058708] NET: Registered protocol family 16 [ 0.060829] DMA: preallocated 256 KiB pool for atomic coherent allocations [ 0.062237] cpuidle: using governor ladder [ 0.062259] cpuidle: using governor menu [ 0.065567] No ATAGs? [ 0.065599] hw-breakpoint: found 5 (+1 reserved) breakpoint and 1 watchpoint registers. [ 0.065616] hw-breakpoint: maximum watchpoint size is 4 bytes. [ 0.067452] Serial: AMBA PL011 UART driver [ 0.079287] vgaarb: loaded [ 0.080102] SCSI subsystem initialized [ 0.080575] usbcore: registered new interface driver usbfs [ 0.080666] usbcore: registered new interface driver hub [ 0.080729] usbcore: registered new device driver usb [ 0.081506] pps_core: LinuxPPS API ver. 1 registered [ 0.081531] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@xxxxxxxx> [ 0.081583] PTP clock support registered [ 0.081736] EDAC MC: Ver: 3.0.0 [ 0.083594] clocksource: Switched to clocksource arm_global_timer [ 0.093107] NET: Registered protocol family 2 [ 0.093671] TCP established hash table entries: 4096 (order: 2, 16384 bytes) [ 0.093741] TCP bind hash table entries: 4096 (order: 3, 32768 bytes) [ 0.093829] TCP: Hash tables configured (established 4096 bind 4096) [ 0.093928] UDP hash table entries: 256 (order: 1, 8192 bytes) [ 0.093966] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes) [ 0.094167] NET: Registered protocol family 1 [ 0.094500] RPC: Registered named UNIX socket transport module. [ 0.094527] RPC: Registered udp transport module. [ 0.094545] RPC: Registered tcp transport module. [ 0.094561] RPC: Registered tcp NFSv4.1 backchannel transport module. [ 0.094979] Unpacking initramfs... [ 0.322686] Freeing initrd memory: 2696K (df8a9000 - dfb4b000) [ 0.323993] futex hash table entries: 256 (order: 2, 16384 bytes) [ 0.334409] squashfs: version 4.0 (2009/01/31) Phillip Lougher [ 0.335242] NFS: Registering the id_resolver key type [ 0.335292] Key type id_resolver registered [ 0.335312] Key type id_legacy registered [ 0.335399] ntfs: driver 2.1.32 [Flags: R/O]. [ 0.336856] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 249) [ 0.336904] io scheduler noop registered [ 0.336931] io scheduler deadline registered [ 0.336978] io scheduler cfq registered (default) [ 0.401831] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled [ 0.404147] 54006800.serial: ttyS0 at MMIO 0x54006800 (irq = 20, base_baud = 2304000) is a 16550A [ 0.951091] console [ttyS0] enabled [ 0.955379] 54006a00.serial: ttyS2 at MMIO 0x54006a00 (irq = 21, base_baud = 2304000) is a 16550A [ 0.965022] 54006b00.serial: ttyS3 at MMIO 0x54006b00 (irq = 22, base_baud = 2304000) is a 16550A [ 0.974424] SuperH (H)SCI(F) driver initialized [ 0.979508] msm_serial: driver initialized [ 0.983874] STMicroelectronics ASC driver initialized [ 0.989910] [drm] Initialized drm 1.1.0 20060810 [ 1.001899] loop: module loaded [ 1.010147] libphy: Fixed MDIO Bus: probed [ 1.014941] CAN device driver interface [ 1.019517] igb: Intel(R) Gigabit Ethernet Network Driver - version 5.3.0-k [ 1.026502] igb: Copyright (c) 2007-2014 Intel Corporation. [ 1.033741] pegasus: v0.9.3 (2013/04/25), Pegasus/Pegasus II USB Ethernet driver [ 1.041240] usbcore: registered new interface driver pegasus [ 1.046982] usbcore: registered new interface driver asix [ 1.052454] usbcore: registered new interface driver ax88179_178a [ 1.058618] usbcore: registered new interface driver cdc_ether [ 1.064534] usbcore: registered new interface driver smsc75xx [ 1.070356] usbcore: registered new interface driver smsc95xx [ 1.076166] usbcore: registered new interface driver net1080 [ 1.081893] usbcore: registered new interface driver cdc_subset [ 1.087873] usbcore: registered new interface driver zaurus [ 1.093549] usbcore: registered new interface driver cdc_ncm [ 1.100256] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver [ 1.106808] ehci-pci: EHCI PCI platform driver [ 1.111318] ehci-platform: EHCI generic platform driver [ 1.116775] ehci-platform 5a800100.usb: EHCI Host Controller [ 1.122482] ehci-platform 5a800100.usb: new USB bus registered, assigned bus number 1 [ 1.133312] ehci-platform 5a800100.usb: can't setup: -110 [ 1.138735] ehci-platform 5a800100.usb: USB bus 1 deregistered [ 1.144607] ehci-platform: probe of 5a800100.usb failed with error -110 [ 1.151342] ehci-platform 5a810100.usb: EHCI Host Controller [ 1.157037] ehci-platform 5a810100.usb: new USB bus registered, assigned bus number 1 [ 1.167674] ehci-platform 5a810100.usb: can't setup: -110 [ 1.173089] ehci-platform 5a810100.usb: USB bus 1 deregistered [ 1.178951] ehci-platform: probe of 5a810100.usb failed with error -110 [ 1.185626] ehci-omap: OMAP-EHCI Host Controller driver [ 1.190993] ehci-orion: EHCI orion driver [ 1.195108] SPEAr-ehci: EHCI SPEAr driver [ 1.199225] ehci-st: EHCI STMicroelectronics driver [ 1.204208] ehci-exynos: EHCI EXYNOS driver [ 1.208486] ehci-atmel: EHCI Atmel driver [ 1.212595] tegra-ehci: Tegra EHCI driver [ 1.216729] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver [ 1.222942] ohci-pci: OHCI PCI platform driver [ 1.227467] ohci-platform: OHCI generic platform driver [ 1.232801] ohci-omap3: OHCI OMAP3 driver [ 1.236912] SPEAr-ohci: OHCI SPEAr driver [ 1.241024] ohci-st: OHCI STMicroelectronics driver [ 1.246008] ohci-atmel: OHCI Atmel driver [ 1.250357] usbcore: registered new interface driver usb-storage [ 1.257408] mousedev: PS/2 mouse device common for all mice [ 1.265660] i2c /dev entries driver [ 1.275568] sdhci: Secure Digital Host Controller Interface driver [ 1.281778] sdhci: Copyright(c) Pierre Ossman [ 1.286997] Synopsys Designware Multimedia Card Interface Driver [ 1.293653] sdhci-pltfm: SDHCI platform and OF driver helper [ 1.300493] ledtrig-cpu: registered to indicate activity on CPUs [ 1.306752] usbcore: registered new interface driver usbhid [ 1.312342] usbhid: USB HID core driver [ 1.319662] NET: Registered protocol family 10 [ 1.324929] sit: IPv6 over IPv4 tunneling driver [ 1.330198] NET: Registered protocol family 17 [ 1.334677] can: controller area network core (rev 20120528 abi 9) [ 1.340946] NET: Registered protocol family 29 [ 1.345410] can: raw protocol (rev 20120528) [ 1.349693] can: broadcast manager protocol (rev 20120528 t) [ 1.355367] can: netlink gateway (rev 20130117) max_hops=1 [ 1.361312] Key type dns_resolver registered [ 1.365708] ThumbEE CPU extension supported. [ 1.370010] Registering SWP/SWPB emulation handler [ 1.376863] hctosys: unable to open rtc device (rtc0) [ 1.384956] Freeing unused kernel memory: 1048K (c0dce000 - c0ed4000) Starting logging: OK Initializing random number generator... [ 1.453460] random: dd urandom read with 0 bits of entropy available done. Waiting for network interfaces to appear ok Starting network... Welcome to Buildroot buildroot login: -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
