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Description of problem: I have a USB serial port device, a RR CirKits LCC Buffer USB, which shows up as: usb 2-1.1: new full speed USB device number 6 using ehci_hcd usb 2-1.1: New USB device found, idVendor=04d8, idProduct=000a usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0 usb 2-1.1: Product: Simple CDC Device Demo usb 2-1.1: Manufacturer: Microchip Technology Inc. usb 2-1.1: configuration #1 chosen from 1 choice cdc_acm 2-1.1:1.0: This device cannot do calls on its own. It is not a modem. cdc_acm 2-1.1:1.0: ttyACM0: USB ACM device usbcore: registered new interface driver cdc_acm cdc_acm: v0.26:USB Abstract Control Model driver for USB modems and ISDN adapters This device works just fine one one machine (my laptop) and not on another machine (my desktop). Both machines are running the same O/S: CentOS 6.7, with the same kernel (2.6.32-573.12.1.el6.x86_64), both with SELINUX 'enforcing'. I have added myself to the 'dialout' group on both machines. The 'getbooleans' out for both machines are exactly the same. 'ls' on the problem machine shows the device file: sauron.deepsoft.com% ls -lZ /dev/ttyACM0 crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM0 but minicom fails: sauron.deepsoft.com% minicom Device /dev/ttyACM0 access failed: No such file or directory. The only real differences between the machines are that the desktop machine has several VMs defined (under KVM) and one running. Also the desktop machine has a PCI quad serial port card and has the 8250.nr_uarts kernel parameter set to 8 (I use one of these ports for a dialup [analog phone] modem for Internet access). I cannot figure out what is different between the two machines. Version-Release number of selected component (if applicable):minicom-2.3-6.1.el6 How reproducible: Very Steps to Reproduce: 1. Insert USB cable 2. Try to access the device (typically with minicom, but any software that can work with a serial port also fails). 3. Actual results: The device is claimed no to exist. Expected results: Serial I/O results. Additional info: Works on one machine, but not the other. Both machines are running the *same* system software.
OK, I just did a yum update, got a new kernel and glibc. The problem persists: sauron.deepsoft.com% dir -lZ /dev/ttyACM0 crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM0 sauron.deepsoft.com% minicom Device /dev/ttyACM0 access failed: No such file or directory. sauron.deepsoft.com% sudo minicom [sudo] password for heller: Device /dev/ttyACM0 access failed: No such file or directory. sauron.deepsoft.com% uname -a Linux sauron.deepsoft.com 2.6.32-573.18.1.el6.x86_64 #1 SMP Tue Feb 9 22:46:17 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux sauron.deepsoft.com% rpm -q glibc glibc-2.12-1.166.el6_7.7.x86_64 glibc-2.12-1.166.el6_7.7.i686 But it still works on gollum, with the same new kernel and glibc: gollum.deepsoft.com% dir -lZ /dev/ttyACM0 crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM0 gollum.deepsoft.com% uname -a Linux gollum.deepsoft.com 2.6.32-573.18.1.el6.x86_64 #1 SMP Tue Feb 9 22:46:17 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux gollum.deepsoft.com% rpm -q glibc glibc-2.12-1.166.el6_7.7.x86_64 I also tried setting selinux in 'permissive' mode, but that did not help either. Am I the only one with this problem?
I'm just placeholder assignee here, but I assume lockdev can be the culprit here. If the device file is locked, access may fail. You can probably remove the lockfile and try it again.
I just tried this device on another CentOS 6 machine (one that *also* has VMs on it) and things work just fine. So it isn't KVM. It looks like there is something *specific* about this device on my machine. I have no clue what. I tried a different device, which also uses the cdc_acm kmod driver (and the same device file name -- /dev/ttyACM0) and it works on my machine. I don't know what it is that is causing this problem. I do run with some kernel params -- I increase the number of UARTs, because I have a quad RS232 port card and I also increase the number of loop devices, because I do a lot of loopback mounts, but I don't think that could be the problem. Does anyone have any ideas of where I should look? The only thing 'distintive' about by desktop is that it has an AMD processor and a nVidia chipset motherboard and the machines where the device works are all Intel processor / Intel chipset machines. Does that even make sense?
Here is some more info: usb 2-1.4.1: new full speed USB device number 18 using ehci_hcd usb 2-1.4.1: New USB device found, idVendor=04d8, idProduct=000a usb 2-1.4.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0 usb 2-1.4.1: Product: Simple CDC Device Demo usb 2-1.4.1: Manufacturer: Microchip Technology Inc. usb 2-1.4.1: configuration #1 chosen from 1 choice cdc_acm 2-1.4.1:1.0: This device cannot do calls on its own. It is not a modem. cdc_acm 2-1.4.1:1.0: ttyACM0: USB ACM device usb 2-1.4.1: USB disconnect, device number 18 sauron.deepsoft.com% dir /var/lock/ dmraid/ iscsi/ LCK..ttyS4 lvm/ subsys/ sauron.deepsoft.com% groups users dialout lock deepsoft mirror sauron.deepsoft.com% dir -l /dev/ttyACM0 crw-rw----. 1 root dialout 166, 0 Mar 5 09:08 /dev/ttyACM0 sauron.deepsoft.com% minicom Device /dev/ttyACM0 access failed: No such file or directory. sauron.deepsoft.com% lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 004: ID 04f9:003b Brother Industries, Ltd Bus 004 Device 002: ID 046d:c055 Logitech, Inc. Bus 005 Device 002: ID 051d:0002 American Power Conversion Uninterruptible Power Supply Bus 005 Device 003: ID 040b:2000 Weltrend Semiconductor Bus 002 Device 016: ID 05e3:0608 Genesys Logic, Inc. Hub Bus 002 Device 017: ID 05e3:0608 Genesys Logic, Inc. Hub Bus 002 Device 019: ID 04d8:000a Microchip Technology, Inc. CDC RS-232 Emulation Demo Kernel modules: Module Size Used by dm_snapshot 32297 0 dm_bufio 20372 1 dm_snapshot ppp_deflate 4168 0 zlib_deflate 21629 1 ppp_deflate ppp_async 7858 1 crc_ccitt 1717 1 ppp_async ppp_generic 25398 6 ppp_deflate,ppp_async slhc 5805 1 ppp_generic cdc_acm 19622 0 fuse 79892 0 ebtable_nat 2009 0 ebtables 18135 1 ebtable_nat xt_CHECKSUM 1303 0 iptable_mangle 3349 0 autofs4 27000 15 w83627ehf 23844 0 hwmon_vid 3132 1 w83627ehf 8021q 20362 0 garp 7152 1 8021q bridge 84537 0 stp 2218 2 garp,bridge llc 5418 3 garp,bridge,stp ipt_REJECT 2351 2 iptable_filter 2793 1 ipt_MASQUERADE 2338 1 iptable_nat 5923 1 nf_nat 22676 2 ipt_MASQUERADE,iptable_nat nf_conntrack_ipv4 9154 6 iptable_nat,nf_nat nf_defrag_ipv4 1483 1 nf_conntrack_ipv4 ip_tables 17831 3 iptable_mangle,iptable_filter,iptable_nat ip6t_REJECT 4340 2 nf_conntrack_ipv6 7985 4 nf_defrag_ipv6 26468 1 nf_conntrack_ipv6 xt_state 1492 7 nf_conntrack 79206 6 ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_ipv4,nf_conntrack_ipv6,xt_state ip6table_filter 2889 1 ip6_tables 18732 1 ip6table_filter ipv6 335525 56 bridge,ip6t_REJECT,nf_conntrack_ipv6,nf_defrag_ipv6 ext3 240580 10 jbd 80652 1 ext3 ext2 68236 1 vhost_net 29168 1 macvtap 10775 1 vhost_net macvlan 10324 1 macvtap tun 16934 3 vhost_net kvm_amd 40635 3 kvm 345460 1 kvm_amd uinput 8120 0 microcode 112205 0 usblp 11734 0 sg 29318 0 serio_raw 4626 0 snd_hda_codec_realtek 73538 1 k10temp 3545 0 snd_hda_codec_generic 62014 1 snd_hda_codec_realtek edac_core 46645 0 edac_mce_amd 15615 0 shpchp 29130 0 forcedeth 60609 0 snd_hda_intel 55222 2 snd_hda_codec 136309 3 snd_hda_codec_realtek,snd_hda_codec_generic,snd_hda_intel snd_hwdep 7100 1 snd_hda_codec snd_seq 60769 0 snd_seq_device 7277 1 snd_seq snd_pcm 93793 2 snd_hda_intel,snd_hda_codec snd_timer 22747 2 snd_seq,snd_pcm snd 73783 13 snd_hda_codec_realtek,snd_hda_codec_generic,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_seq,snd_seq_device,snd_pcm,snd_timer soundcore 7958 2 snd_hda_codec,snd snd_page_alloc 8856 2 snd_hda_intel,snd_pcm i2c_nforce2 6328 0 ext4 378683 1 jbd2 93252 1 ext4 mbcache 8193 3 ext3,ext2,ext4 raid1 32705 2 sd_mod 37030 6 crc_t10dif 1209 1 sd_mod sr_mod 15049 0 cdrom 39085 1 sr_mod aic7xxx 117856 0 scsi_transport_spi 25447 1 aic7xxx firewire_ohci 24695 0 firewire_core 50151 1 firewire_ohci crc_itu_t 1717 1 firewire_core ahci 42738 4 pata_acpi 3701 0 ata_generic 3837 0 pata_amd 11900 0 nouveau 1340573 2 ttm 89408 1 nouveau drm_kms_helper 88766 1 nouveau drm 320992 5 nouveau,ttm,drm_kms_helper i2c_algo_bit 5711 1 nouveau i2c_core 29132 5 i2c_nforce2,nouveau,drm_kms_helper,drm,i2c_algo_bit mxm_wmi 1967 1 nouveau video 21654 1 nouveau output 2409 1 video wmi 6287 2 nouveau,mxm_wmi dm_mirror 14384 0 dm_region_hash 12085 1 dm_mirror dm_log 9930 2 dm_mirror,dm_region_hash dm_mod 99168 58 dm_snapshot,dm_bufio,dm_mirror,dm_log Kernel version: sauron.deepsoft.com% uname -a Linux sauron.deepsoft.com 2.6.32-573.18.1.el6.x86_64 #1 SMP Tue Feb 9 22:46:17 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux Kernel param list (from /boot/grub/grub.conf): kernel /vmlinuz-2.6.32-573.18.1.el6.x86_64 ro root=/dev/mapper/sauron-c6_root 8250.nr_uarts=8 max_loop=32 rd_MD_UUID=3c4a1e48:8aa377f6:9e3b46bf:71a46887 rd_NO_LUKS LANG=en_US.UTF-8 rd_LVM_LV=sauron/swap SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rd_LVM_LV=sauron/c6_root crashkernel=auto PCI bus: 00:00.0 RAM memory: NVIDIA Corporation MCP78S [GeForce 8200] Memory Controller (rev a2) 00:01.0 ISA bridge: NVIDIA Corporation MCP78S [GeForce 8200] LPC Bridge (rev a2) 00:01.1 SMBus: NVIDIA Corporation MCP78S [GeForce 8200] SMBus (rev a1) 00:01.2 RAM memory: NVIDIA Corporation MCP78S [GeForce 8200] Memory Controller (rev a1) 00:01.3 Co-processor: NVIDIA Corporation MCP78S [GeForce 8200] Co-Processor (rev a2) 00:01.4 RAM memory: NVIDIA Corporation MCP78S [GeForce 8200] Memory Controller (rev a1) 00:02.0 USB controller: NVIDIA Corporation MCP78S [GeForce 8200] OHCI USB 1.1 Controller (rev a1) 00:02.1 USB controller: NVIDIA Corporation MCP78S [GeForce 8200] EHCI USB 2.0 Controller (rev a1) 00:04.0 USB controller: NVIDIA Corporation MCP78S [GeForce 8200] OHCI USB 1.1 Controller (rev a1) 00:04.1 USB controller: NVIDIA Corporation MCP78S [GeForce 8200] EHCI USB 2.0 Controller (rev a1) 00:06.0 IDE interface: NVIDIA Corporation MCP78S [GeForce 8200] IDE (rev a1) 00:07.0 Audio device: NVIDIA Corporation MCP72XE/MCP72P/MCP78U/MCP78S High Definition Audio (rev a1) 00:08.0 PCI bridge: NVIDIA Corporation MCP78S [GeForce 8200] PCI Bridge (rev a1) 00:09.0 SATA controller: NVIDIA Corporation MCP78S [GeForce 8200] AHCI Controller (rev a2) 00:0a.0 Ethernet controller: NVIDIA Corporation MCP77 Ethernet (rev a2) 00:0b.0 PCI bridge: NVIDIA Corporation MCP78S [GeForce 8200] PCI Express Bridge (rev a1) 00:10.0 PCI bridge: NVIDIA Corporation MCP78S [GeForce 8200] PCI Express Bridge (rev a1) 00:12.0 PCI bridge: NVIDIA Corporation MCP78S [GeForce 8200] PCI Express Bridge (rev a1) 00:13.0 PCI bridge: NVIDIA Corporation MCP78S [GeForce 8200] PCI Bridge (rev a1) 00:14.0 PCI bridge: NVIDIA Corporation MCP78S [GeForce 8200] PCI Bridge (rev a1) 00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 10h Processor HyperTransport Configuration 00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 10h Processor Address Map 00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 10h Processor DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 10h Processor Miscellaneous Control 00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 10h Processor Link Control 01:07.0 USB controller: VIA Technologies, Inc. VT82xx/62xx UHCI USB 1.1 Controller (rev 61) 01:07.1 USB controller: VIA Technologies, Inc. VT82xx/62xx UHCI USB 1.1 Controller (rev 61) 01:07.2 USB controller: VIA Technologies, Inc. USB 2.0 (rev 63) 01:07.3 FireWire (IEEE 1394): VIA Technologies, Inc. VT6306/7/8 [Fire II(M)] IEEE 1394 OHCI Controller (rev 46) 01:09.0 SCSI storage controller: Adaptec AIC-7892A U160/m (rev 02) 01:0a.0 Serial controller: Lava Computer mfg Inc Quattro-PCI A 01:0a.1 Serial controller: Lava Computer mfg Inc Quattro-PCI B 02:00.0 VGA compatible controller: NVIDIA Corporation C77 [GeForce 8200] (rev a2) Does any of this help find out what is wrong?
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