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Re: Monitor Madness
by Aljerin Butler,Jr. Aug. 17, 2018

Aug. 17, 2018

Try doing some research here. | | | | Howtos, tips, tutorials; IT ebooks Super User | | | On Wednesday, August 8, 2018, 9:53:12 PM EDT, Krichevsky, Nicholas Jacob <njkrichevsky(a)wpi.edu> wrote: Hey all - By an interesting turn of events, my fellow interns and I were given the opportunity to build a computer to theoretically drive 192 monitors. Yes, really. We're running into a bit of a brick wall, so I figured I'd reach out and see if anyone had any crazy ideas that just might work. This project started because of a certain obsession of our CEO to drive as many monitors off one PC as possible. We put together a build using8x Radeon 7870s with 6x Mini DisplayPort outputs (the price spiked after we bought these for some reason) with2x Intel Xeon E5-2630 V4 , all tied together in a SuperMicro 4028GR-TR2. Limiting the cards to PCIE 8x, we should be able to drive all 8 with 16 PCIE lanes to spare. Because the Mini DisplayPorts follow the DisplayPort 2.1 spec, we were hoping to use MST with48 of these MST hubs from Monoprice (which we actually got on sale!). This would allow us to drive four displays @ 1080p off one Mini DisplayPort, allowing us to drive 24 monitors off one card, across 8 cards, totaling 192 monitors. With this all in mind, and the knowledge that we may have to write some funky Xorg configs, we pulled the trigger on all of it, and would attempt to drive as many monitors as we had on hand in the office. We decided to load Fedora on this machine, which should be able to drive MST with the included amdgpu driver, thanks to patches that were added to kernel 4.15, and some DC display code settings that were enabled in kernel 4.17. With all of this, we were able to successfully drive ... two displays off each MST hub, instead of the expected four. Not as fruitful as we may have hoped, but hey, 96 monitors would still be awesome. Out of sheer curiosity, we threw Windows on another SSD, and discovered that Windows could drive four displays off each MST hub, but we were getting hard limited to six monitors per card, no matter what we tried. We hypothesized that this might be due to theproprietary AMD driver setting an arbitrary limit, and thought we might be able to still pull off the 12 monitors per card in Linux. A couple of small scripts later, we were up and running with six monitors on one card. Upon adding the seventh and re-running our script, we were greeted with the following. [monitormadness@monitor-madness ~]$ python3 set-monitors.py Executing `xrandr -d :0 --output DisplayPort-3-1-1 --mode 1920x1080 --output DisplayPort-0-1-1 --mode 1920x1080 --output DisplayPort-1-1-1 --mode 1920x1080 --output DisplayPort-0-1-2 --mode 1920x1080 --output DisplayPort-3-1-1 --mode 1920x1080 --output DisplayPort-1-1-2 --mode 1920x1080 --output DisplayPort-4-1-1 --mode 1920x1080` xrandr: cannot find crtc for output DisplayPort-4-1-1 We ran xrandr --listproviders to see what we got. With two GPUs connected, we got the following. [monitormadness@monitor-madness ~]$ xrandr --listproviders -d :0Providers: number : 2Provider 0: id: 0x8d cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 30 associated providers: 1 name:PITCAIRN @ pci:0000:04:00.0Provider 1: id: 0x4b cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 6 associated providers: 1 name:PITCAIRN @ pci:0000:06:00.0 Looks like we can only get 6 CRTCs per card. This is where I reach out to you all. Does anyone know of some Xorg or kernel flag trickery we can use to get more outputs for our buck with the limited number of CRTCs? I don't quite know enough about how video cards work to make an informed decision about what's going on, but my hypothesis is that the card's firmware is what transmits how many outputs we can use, so we may be SOL in the department of getting more CRTCs, but perhaps there may be some way to trick Xorg into rendering the content of one CRTC across multiple monitors? Not sure. Would love to hear what you all think. Thanks for taking the time to read this! :) _______________________________________________ WLUG mailing list -- wlug(a)lists.wlug.org To unsubscribe send an email to wlug-leave(a)lists.wlug.org

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Reconnecting with my media drive
by Richard Klein Aug. 9, 2018

Aug. 9, 2018

When I was running Debian, I had most of my media segregated on a Seagate SSHD. That's still in the system now that I'm running Mint. I'm trying to get Plex up and running again. The file manager shows the media drive mounted, but shows nothing on it. I don't see it listed in fstab. I don't remember how it was formatted, but I think it's an ext4 drive. What should my next step be? -- Rich

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Monitor Madness
by Krichevsky, Nicholas Jacob Aug. 9, 2018

Aug. 9, 2018

Hey all - By an interesting turn of events, my fellow interns and I were given the opportunity to build a computer to theoretically drive 192 monitors. Yes, really. We're running into a bit of a brick wall, so I figured I'd reach out and see if anyone had any crazy ideas that just might work. This project started because of a certain obsession of our CEO to drive as many monitors off one PC as possible. We put together a build using 8x Radeon 7870s with 6x Mini DisplayPort outputs<https://www.newegg.com/Product/Product.aspx?Item=9SIA0AJ3BU1115&cm_re=Visio…> (the price spiked after we bought these for some reason) with 2x Intel Xeon E5-2630 V4 <https://www.newegg.com/Product/Product.aspx?Item=N82E16819117630> , all tied together in a SuperMicro 4028GR-TR2<https://www.supermicro.com/products/system/4u/4028/SYS-4028GR-TR2.cfm>. Limiting the cards to PCIE 8x, we should be able to drive all 8 with 16 PCIE lanes to spare. Because the Mini DisplayPorts follow the DisplayPort 2.1 spec, we were hoping to use MST with 48 of these MST hubs from Monoprice<https://www.monoprice.com/product?c_id=104&cp_id=10428&cs_id=1042802&p_id=2…> (which we actually got on sale!). This would allow us to drive four displays @ 1080p off one Mini DisplayPort, allowing us to drive 24 monitors off one card, across 8 cards, totaling 192 monitors. With this all in mind, and the knowledge that we may have to write some funky Xorg configs, we pulled the trigger on all of it, and would attempt to drive as many monitors as we had on hand in the office. We decided to load Fedora on this machine, which should be able to drive MST with the included amdgpu driver, thanks to patches that were added to kernel 4.15, and some DC display code settings that were enabled in kernel 4.17. With all of this, we were able to successfully drive ... two displays off each MST hub, instead of the expected four. Not as fruitful as we may have hoped, but hey, 96 monitors would still be awesome. Out of sheer curiosity, we threw Windows on another SSD, and discovered that Windows could drive four displays off each MST hub, but we were getting hard limited to six monitors per card, no matter what we tried. We hypothesized that this might be due to the proprietary AMD driver setting an arbitrary limit, and thought we might be able to still pull off the 12 monitors per card in Linux. A couple of small scripts later, we were up and running with six monitors on one card. Upon adding the seventh and re-running our script, we were greeted with the following. [monitormadness@monitor-madness ~]$ python3 set-monitors.py Executing `xrandr -d :0 --output DisplayPort-3-1-1 --mode 1920x1080 --output DisplayPort-0-1-1 --mode 1920x1080 --output DisplayPort-1-1-1 --mode 1920x1080 --output DisplayPort-0-1-2 --mode 1920x1080 --output DisplayPort-3-1-1 --mode 1920x1080 --output DisplayPort-1-1-2 --mode 1920x1080 --output DisplayPort-4-1-1 --mode 1920x1080` xrandr: cannot find crtc for output DisplayPort-4-1-1 We ran xrandr --listproviders to see what we got. With two GPUs connected, we got the following. [monitormadness@monitor-madness ~]$ xrandr --listproviders -d :0 Providers: number : 2 Provider 0: id: 0x8d cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 30 associated providers: 1 name:PITCAIRN @ pci:0000:04:00.0 Provider 1: id: 0x4b cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 6 associated providers: 1 name:PITCAIRN @ pci:0000:06:00.0 Looks like we can only get 6 CRTCs per card. This is where I reach out to you all. Does anyone know of some Xorg or kernel flag trickery we can use to get more outputs for our buck with the limited number of CRTCs? I don't quite know enough about how video cards work to make an informed decision about what's going on, but my hypothesis is that the card's firmware is what transmits how many outputs we can use, so we may be SOL in the department of getting more CRTCs, but perhaps there may be some way to trick Xorg into rendering the content of one CRTC across multiple monitors? Not sure. Would love to hear what you all think. Thanks for taking the time to read this! :)

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Reminder: WLUG Meeting August 9th, 2018! Topic: Bro
by Tim Keller Aug. 6, 2018

Aug. 6, 2018

Hey Gang, We've got a meeting on Thursday! Time @ Location: 7pm @ WPI Mid Century Room (Rm 331) aka, the usual spot Topic: Bro Network Security Monitor Presenter: Eric Martin Veteran WLUG member Eric Martin will be giving a talk about "Bro" What's Bro? Bro is a FOSS framework and event engine for analyzing network traffic. First developed at LBNL in 1995 it is used on public, private and personal networks provide robust indepth network usage and threat analysis. Check out http://www.bro.org for more details. Eric's talk will be focused around using Bro to understand the flow of traffic around devices on our home network. As we add an ever increasing set of devices that have the words "IoT" and/or Smart in their names, it matters that we know what these devices are doing and who they're talking to. Thanks, Tim. -- I am leery of the allegiances of any politician who refers to their constituents as "consumers".

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Desktop distro
by Richard Klein Aug. 6, 2018

Aug. 6, 2018

I'm having trouble deciding which distro to install on my new SSD. It's the only desktop computer in the house, so it's used for web, email, etc, plus it's a Plex server. DistroWatch.com shows Manjaro being really popular right now, but I've never heard of it. It's based on Arch, which I've heard of, but never tried. I see that Arch uses Pacman for a package manager. I'm used to APT; I'm not sure if I'd like Pacman. So anyway, I thought I'd ask for suggestions. -- Rich

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Reminder! Meeting August 9th 2018 at 7pm
by Tim Keller Aug. 5, 2018

Aug. 5, 2018

Hey Gang! We've got a WLUG meeting August 9th! Location: Campus Center Mid Century Room (rm 331) at 7pm. Topic: I'm working on that!!! If there's something cool you've been working on, or would like to show off, let me know! As usual refreshments and snacks will be provided. Afterwards we'll head off for dinner and keep up the conversation! Thanks, Tim. -- I am leery of the allegiances of any politician who refers to their constituents as "consumers".

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Microsoft PowerShell
by Richard Klein Aug. 1, 2018

Aug. 1, 2018

Microsoft PowerShell is now available as a Snap: https://betanews.com/2018/07/20/microsoft-powershell-core-linux-snap/ -- Rich

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Full Home folder
by Richard Klein July 30, 2018

July 30, 2018

I found today that my Home folder is full. The culprit seems to have been a roughly 1/2 terabyte .xsession-errors file. I deleted it, but 'emptying the trash' didn't seem to be clearing any space. I found that everything I'd thought I'd deleted recently seemed to still be sitting in $uname/.local/share/Trash. I selected everything in that folder and typed shift+delete. Now nothing shows in the Trash folder, but my Home folder is still full. I rebooted, and that's still the case. What now? [code] Debian-Precision:~$ uname -a Linux Debian-Precision 4.9.0-6-amd64 #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) x86_64 GNU/Linux [/code] -- Rich

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Re: Full Home folder
by Gelman, Ian S July 29, 2018

July 29, 2018

oops - forgot to add the mailer On Jul 29, 2018, at 4:41 PM, Richard Klein <rich(a)richardklein.org<mailto:rich@richardklein.org>> wrote: Debian-Precision:~$ sudo du -h / --max-depth=1 | sort -h [sudo] password for $uname: du: cannot read directory '/proc/1411/task/1411/net': Invalid argument du: cannot read directory '/proc/1411/net': Invalid argument du: cannot access '/proc/3892/task/3892/fd/4': No such file or directory du: cannot access '/proc/3892/task/3892/fdinfo/4': No such file or directory du: cannot access '/proc/3892/fd/3': No such file or directory du: cannot access '/proc/3892/fdinfo/3': No such file or directory 0 /proc 0 /sys 4.0K /lib64 4.0K /mnt 4.0K /srv 16K /lost+found 20K /dev 72K /tmp 9.2M /run 9.3M /bin 9.5M /etc 11M /sbin 19M /root 34M /boot 181M /opt 233M /lib 1.1G /home 1.1G /var 1.7G /snap 3.1G /usr 730G /media 737G / On Sun, Jul 29, 2018 at 4:37 PM Gelman, Ian S <isgelman(a)wpi.edu<mailto:isgelman@wpi.edu>> wrote: What does the output of du (disk-usage) give? Try this: sudo du -h / --max-depth=1 | sort -h On Jul 29, 2018, at 4:26 PM, Richard Klein <rich(a)richardklein.org<mailto:rich@richardklein.org>> wrote: I found today that my Home folder is full. The culprit seems to have been a roughly 1/2 terabyte .xsession-errors file. I deleted it, but 'emptying the trash' didn't seem to be clearing any space. I found that everything I'd thought I'd deleted recently seemed to still be sitting in $uname/.local/share/Trash. I selected everything in that folder and typed shift+delete. Now nothing shows in the Trash folder, but my Home folder is still full. I rebooted, and that's still the case. What now? [code] Debian-Precision:~$ uname -a Linux Debian-Precision 4.9.0-6-amd64 #1 SMP Debian 4.9.88-1+deb9u1 (2018-05-07) x86_64 GNU/Linux [/code] -- Rich _______________________________________________ WLUG mailing list -- wlug(a)lists.wlug.org<mailto:wlug@lists.wlug.org> To unsubscribe send an email to wlug-leave(a)lists.wlug.org<mailto:wlug-leave@lists.wlug.org>

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IMPORTANT: WLUG Mailing List Move Complete
by Chuck Anderson July 21, 2018

July 21, 2018

By now everyone should have received a welcome message from the new list server, wlug(a)lists.wlug.org, along with instructions for setting your password. I'm still working on getting the archives moved over. Please use only the new list address wlug(a)lists.wlug.org to post--if you use an old address you'll get a reminder to use the new one, at least until a few weeks from now when the old server will have to go offline. I'd also like to thank our generous host http://mailman3.com for providing our new mailing list and Hyperkitty web forum free of charge. Thanks, Chuck On Thu, Jul 19, 2018 at 04:57:01PM -0400, Chuck Anderson wrote: > After 18+ years of the WLUG mailing list being graciously hosted on > the WPI campus network at no cost to WLUG, we must move to an external > mailing list host as WPI prepares to shut down its Linux email > infrastructure after moving to Microsoft Office 365 in the cloud. > Phase 1 begins Monday, July 23, 2018, but the shutdown for third-party > domains like wlug.org is planned for mid- to late-August. > > Luckily, we have a new sponsor who has generously offered to host our > mailing list at no cost on Mailman 3 with Hyperkitty! We are > currently setting up the new mailing list and working out the details, > but I wanted to send out a "heads up" message to everyone before > anything changes. > > The plan is to set up the new host in parallel with the existing host, > but this necessitates a change in the mailing list address. I also > plan to copy the existing subscriber list (and archives if possible) > over to the new list, but if that isn't possible I'll let everyone > know. > > More details will be coming soon. I'll also update the WLUG website > http://www.wlug.org/ with the new mailing list details when we are > ready, so watch that space in case we lose the ability to send to the > old list! Worst case, we have the subscriber list backed up and could > send an email to everyone individually if it becomes necessary. > > Thanks, > Chuck

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