04-12-2014 08:43 AM
I am desperately trying to find out the best way of adding a third display to my current setup.
My current setup is as follows:
- Lenovo X220
- Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz
- Ubuntu Linux Trusty LTS 14.04
- Using built-in display (1366x768)
- Using external display connected via passive DisplayPort to DVI adapter (1680x1050)
Now I would like to add a third display that is the same model as the display already connected via DisplayPort.
The article http://forums.lenovo.com/t5/X-Series-ThinkPad-Laptops/How-to-attach-more-than-two-external-monitors-... lists options for connecting further displays to the X220.
My conclusions so far are as follows:
I do not have USB 3.0 and as such can not use the USB 3.0 dock. Furthermore the USB 3.0 dock seems to use a DisplayLink chip that is not properly supported on Linux.
I do not want to use an eGPU as this seems rather expensive and overkill.
I would prefer not to use a USB-to-DVI Adapter because these seem to have rather bad Linux support and possibly suboptimal performance on USB 2.0.
Option 2 (using an Lenovo DisplayPort to Dual DisplayPort Adapter) sounds like the best idea so far. According to http://forums.lenovo.com/t5/A-M-and-Edge-Series-ThinkCentre/M92p-DisplayPort-to-dual-Displayport-ada... this seems to imply that I have to obtain active DisplayPort to DVI adapters as passive ones will not work.
http://www.lenovo.com/shop/americas/content/pdf/system_data/x220_tech_specs.pdf specifies a maximum resolution for DisplayPort of 2560x1600 and considering that the Dual DisplayPort Adapter would present the two external displays as a single 3360x1050 display, I am wondering whether this would actually be working. The review at http://reviews.lenovo.com/8923-en_ca/_000001CC_0000354E_/lenovo-lenovo-displayport-to-dual-displaypo... claims that it is infact working.
I would appreciate if someone could clear up my confusion and confirm/deny my conclusions.
Thanks in advance
04-12-2014 03:44 PM
04-12-2014 05:49 PM
thank you for your input. I am glad it seems to be indeed possible to drive my two displays and the X220 display at the same time.
I have been searching for "star tech displayport to dual dvi splitter" and this device does indeed exactly seem to be what I am looking for. Unfortunately, I can not find it anywhere in stock.
It looks like I could get the DisplayPort to Dual DisplayPort Splitter and two active DisplayPort to DVI adapters for about 100 EUR total. Can you confirm that this would be an alternative to the StarTech SP122DP2DVI? This solution would probably be a bit more expensive as you already pointed out, but it has the benefit of being future proof by also working with two DisplayPort displays.
04-12-2014 06:17 PM
04-15-2014 04:14 AM
The combination of the Lenovo DisplayPort to Dual DisplayPort Adapter and active DVI adapters does not seem to work. Neither on Ubuntu nor on Windows. It seems to retry some sort of synchronisation over and over again.
04-15-2014 11:50 AM
04-15-2014 04:10 PM
04-15-2014 04:51 PM - edited 04-15-2014 05:08 PM
As soon as I plug in the DisplayPort cable which is connected to the Dual DisplayPort Adapter (which in turn is connected to the two active DisplayPort to DVI adapters) the display on the laptop starts flickering (as is normal when plugging in another display) and never stops flickering. The green lights on the Dual DisplayPort Adapter also turn off and on. This never stops.
The following is in dmesg under Ubuntu. The behaviour itself is the same under Windows.
[ 128.346758] ------------[ cut here ]------------
[ 128.346793] WARNING: CPU: 0 PID: 1538 at /build/buildd/linux-3.13.0/drivers/gpu/drm/i915/intel_dp.c:2747 intel_dp_link_down+0x1d2/0x210 [i915]()
[ 128.346795] Modules linked in: xt_multiport acpi_call(OF) tp_smapi(OF) thinkpad_ec(OF) pci_stub vboxpci(OF) vboxnetadp(OF) vboxnetflt(OF) vboxdrv(OF) ctr ccm rfcomm bnep binfmt_misc uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core videodev btusb bluetooth arc4 iwldvm mac80211 joydev ip6t_REJECT xt_hl ip6t_rt nf_conntrack_ipv6 nf_defrag_ipv6 ipt_REJECT xt_LOG xt_limit xt_tcpudp xt_addrtype nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack ip6table_filter ip6_tables nf_conntrack_netbios_ns nf_conntrack_broadcast nf_nat_ftp nf_nat nf_conntrack_ftp nf_conntrack iptable_filter ip_tables x_tables snd_hda_codec_hdmi thinkpad_acpi nvram snd_seq_midi snd_seq_midi_event snd_rawmidi intel_rapl x86_pkg_temp_thermal intel_powerclamp kvm_intel kvm snd_hda_codec_conexant snd_hda_intel psmouse snd_hda_codec serio_raw iwlwifi snd_hwdep snd_seq lpc_ich snd_pcm cfg80211 snd_seq_device snd_page_alloc snd_timer mei_me snd mei soundcore mac_hid parport_pc ppdev coretemp lp parport btrfs xor raid6_pq libcrc32c dm_crypt hid_generic usbhid hid crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd i915 ahci libahci e1000e sdhci_pci sdhci ptp i2c_algo_bit drm_kms_helper pps_core drm wmi video
[ 128.346853] CPU: 0 PID: 1538 Comm: Xorg Tainted: GF W O 3.13.0-24-generic #46-Ubuntu
[ 128.346854] Hardware name: LENOVO 4290W1B/4290W1B, BIOS XXXXXXXX (1.39 ) 07/18/2013
[ 128.346856] 0000000000000009 ffff8802f4e99a80 ffffffff81715a64 0000000000000000
[ 128.346859] ffff8802f4e99ab8 ffffffff810676bd ffff880306cc48c8 ffff880306fd8000
[ 128.346861] ffff88030c929000 0000000080180304 ffff880306848000 ffff8802f4e99ac8
[ 128.346864] Call Trace:
[ 128.346871] [<ffffffff81715a64>] dump_stack+0x45/0x56
[ 128.346875] [<ffffffff810676bd>] warn_slowpath_common+0x7d/0xa0
[ 128.346877] [<ffffffff8106779a>] warn_slowpath_null+0x1a/0x20
[ 128.346890] [<ffffffffa013a062>] intel_dp_link_down+0x1d2/0x210 [i915]
[ 128.346903] [<ffffffffa013e3d0>] intel_disable_dp+0x70/0x80 [i915]
[ 128.346915] [<ffffffffa01234ae>] ironlake_crtc_disable+0x1ae/0x940 [i915]
[ 128.346919] [<ffffffff8160c0c4>] ? consume_skb+0x34/0x80
[ 128.346931] [<ffffffffa012a0f9>] __intel_set_mode+0x2c9/0x9d0 [i915]
[ 128.346942] [<ffffffffa012d346>] intel_set_mode+0x16/0x30 [i915]
[ 128.346953] [<ffffffffa012dbfb>] intel_crtc_set_config+0x7ab/0x9a0 [i915]
[ 128.346967] [<ffffffffa002fe9d>] drm_mode_set_config_internal+0x5d/0xe0 [drm]
[ 128.346979] [<ffffffffa0032d87>] drm_mode_setcrtc+0xf7/0x5e0 [drm]
[ 128.346983] [<ffffffff811cd320>] ? poll_select_copy_remaining+0x130/0x130
[ 128.346992] [<ffffffffa0023c22>] drm_ioctl+0x502/0x630 [drm]
[ 128.346997] [<ffffffff811cc6e0>] do_vfs_ioctl+0x2e0/0x4c0
[ 128.347000] [<ffffffff8109dd84>] ? vtime_account_user+0x54/0x60
[ 128.347003] [<ffffffff811cc941>] SyS_ioctl+0x81/0xa0
[ 128.347006] [<ffffffff8172663f>] tracesys+0xe1/0xe6
[ 128.347008] ---[ end trace b09fc9dbe8b6722c ]---
04-15-2014 05:04 PM