Tag: Xorg

Back to Cinnamon!

Okay after my negative experience I’m now back to try Cinnamon, and I have a quite different story to tell.

First of all, thanks to Julian, I found that the issue I was having with the keyboard only involved my user’s settings, and not the code by itself. After a bit more fiddling around, I found a more detailed case where this happens.

My keyboard layout of choice is the so-called US Alternate International (us alt-intl); unfortunately even with the recent improvements in Input hotplug for Xorg, it seems like configuring Xkb on the configuration file, or on the directories, is not recognized by the evdev driver (at least), which is why I configured it with GNOME, Xfce, and, by reflection, Cinnamon, to change the layout of the keyboard — and that’s where the problem lies. When GNOME3 or Cinnamon are started, and they set the keyboard layout (both do it the same way as in both cases you configure it through GSettings), the Alt_L and Meta keys get somehow swapped… but not in all cases, as Emacs was still getting it right (which meant that just switching the two is not going to help me).

I guess I should track it down even further than this, but for the moment, I solved this by using setxkb in my ~/.xsession file, and that doesn’t seem to cause any trouble.

The other issue I reported, was that clutter is unstable when using nvidia hardware; to be precise, the issue is with nvidia-drivers (surprised?), and it’s actually the second issue that I find with their drivers in the last few weeks: the other was Calibre being able to get Xorg to eat so much memory that the system gets unresponsive, just by the sake of being launched, and add to that Skype that was unable to render *at all*….

So I decided to give a try to what Pesa suggested me to solve the Skype (Qt) issue: I decided to try the nouveau driver. Actually I wanted to try that a couple of weeks ago, but after reading through their website I wasn’t sure that my video card (NVIDIA GT218) was supported or if I had to deal with dumping the firmware out of the nvidia drivers and whatever else… but the other day, after screwing my own system over, and needing to boot from SysRescue, I found out that the driver they load is … nouveau, and it worked decently well.

So since this is weekend, and the time was right, I decided to give it a try — and the results are great! Clutter works fine, Cinnamon works fine, and while I haven’t tried anything that is running in OpenGL proper yet (no games), and Google’s Maps GL reports not working with this implementation (not that I care much), it works definitely well enough for what I usually do. I haven’t tried audio out on the DisplayPort connection, but it’s not like I’ve ever tried it before… Suspension works very fine.

And yes for now my experience with Cinnamon is terrific!

Gource visualising feng’s history — A story of Radeon

Or see this on YouTube — and yes this is quite ironic that we’ve uploaded to YouTube the visualised history of a streaming software stack.

The video you can see here is the GIT history of feng the RTSP streaming server me and Luca are working on for the LScube project, previously founded by the Turin Politechnic, visualised through Gource.

While this video has some insights about feng itself, which I’ll discuss on the mailing list of the project soon enough, I’m using this to bring home another point, one even more important I think. You probably remember my problems with ATI HD4350 video card … well, one of the reasons why I didn’t post this video before, even though Gource has been in tree (thanks to Enrico) for a while already, is that it didn’t work too well on my system.

It might not be too obvious, but the way Gource work is by using SDL (and thus OpenGL) to render the visualisation to screen and to (PPM) images – the video is then produced by FFmpeg that takes the sequence of PPM and encodes it in H.264 with x264; no I’m not going to do this with Theora – so you rely on your OpenGL support to produce good results. When 0.24 was being worked on (last January) the r700 Radeon driver, with KMS, had some trouble, and you’d see a full orange or purple frame from time to time, resulting in a not-too-appealing video. Yesterday I bit the bullet, and after dmesg has shown me a request from the kernel to update my userland, I rebuilt the Radeon driver from GIT, and Mesa from the 7.8 branch…

Perfect!

No crashes, no artefacts on glxgears, and no artefacts on Gource either! As you can see from the video above. This is with kernel 2.6.33 vanilla, Mesa 7.8 GIT and Radeon GIT, all with KMS enabled (and the framebuffers work as well!). Kudos to Dave, and all the developers working on Radeon, this is what I call good Free Software!

Just do yourself a favour, and don’t buy videocards with fans… leaving alone nVidia’s screwup with the drivers, all of them failed on me at some point, passive cards instead seem to work much longer, probably because of the lack of moving parts.

International problems

I’m probably one quite strange person myself, that I knew, but I never thought that I would actually have so many problems when it comes to internationalisation, especially on Linux, but not limited to. I have written before that I have problems with my name (and a similar issue happened last week when the MacBook I ordered for my mom was sent by TNT to “Diego Petten?” ­– which wouldn’t then be found properly by the computer system when looking up the package by name), but lately I have been having even worse problems.

One of the first problem has happened while mailing patches with git on mailing list hosted by the Kernel.org servers; my messages were rejected because I used as sender “Diego E. ‘Flameeyes’ Pettenò”, without the double quotes around. For some RFC, when a period is present in the sender or destination names, the whole name has to be quoted in double quotes, but git does not seem to know about that and sends wrong email messages that get rejected. Even adding the escaped quotes in the configuration file didn’t help, so at the end I send my git email with my (new) full name “Diego Elio ‘Flameeyes’ Pettenò” even if it’s tremendously long and boring to read, and Lennart scolded me because now I figure with three different aliases in PulseAudio (on the other hand, ohloh handles that gracefully ).

Little parenthesis, if you’re curious where the “Elio” part comes from; I have legally changed my name, adding “Elio” as part of my first name last fall (it’s not a “second name” in the strict meaning of this term, because Italy does not have the concept of second name, it’s actually part of my first name). The reason for this is that there are four other “Diego Pettenò” in my city, two of which are around my age, and the Italian system is known for mistaking identities; while it does not really make me entirely safe to just add a second name, it should make it less likely that a mistake would happen. I have chosen Elio because that was the name of my grandfather.

So this was one of the problems; nothing really major, and was solved easily. The next problem happened today when I went for writing some notes about extending the guide (for which I still fail to find a publisher; unless I find one, it’ll keep the open donation approach), and, since the amount of blogging about the subject lately has been massive, I wanted to make sure I used the proper typographical quotation marks . It would have been easy to use them from OS X, but from Linux it seems it’s quite more difficult.

On OS X, I can reach the quotation marks on the keys “1” and “2”, adding the Option and Shift keys accordingly (single and double, open and closed); on Linux, with the US English, Alternate International keyboard I’m using, the thing is quite more difficult. The sequence would be something like Right Control, followed by AltGr and ' (or "), followed by < or >; even if I didn’t have to use AltGr to have the proper keys (without AltGr on the Alternate International keyboard the two symbols are “dead keys”, and are used for composing, quite important since I write both English and Italian with the same keyboard), it’s quite a clumsy way to access the two. And it also wouldn’t work with GNU Emacs on X11.

My first idea would have been to use xmodmap to just change the mappings of “1” and “2” to add third and shifted third levels, just like on OS X. Unfortunately adding extra levels with xmodmap seems to only work with the “mode switch” key rather than with the “ISO Level 3” key; the final result is that I had to “sacrifice” the right Command key (I use an Apple keyboard on Linux) to use as “mode switch” (keeping the right Option as Level 3 shift), and then mapping the 1⁄2 keys like I wanted. The result is usable but it also means that all the modifiers on the right side have completely different meaning from what they were designed to, and is not easy to remember all of them.

I thought about using the Keyboard Layout Editor but it requires antlr3 for Python, which is not available in Gentoo and seems to be difficult to update, so for now I’m stuck with this solution; next week when the iMac should arrive I’ll probably spend some more time on the issue (I already spent almost the whole afternoon, more than I should have used), I’d sincerely love to be able to set up the same exact keyboard layout for both systems, so I don’t have to remember in which one I am to get the combinations right; I already publish my custom OSX layout that basically implements the Xorg alternate international layout in OSX (you already have the same layout available in Windows as “US International”, so OSX was the only one lacking that), so I’ll probably just start maintaining layouts for both systems in the future.

And I don’t even want to start talking about setting up proper IME for Japanese under this configuration…

No more breaks

Since this week I’ve been doing lots and lots of work on lscube, of which I wanted to blog but I’m afraid I won’t have much time to do that right now, I wanted to take a break this weekend, to relax, rest, and play a bit. Nothing went like I wanted, and I actually think I won’t try to take again a break like this anytime soon.

Yesterday almost went like I wanted, I worked a bit on my ruby-bombe project, removed the pending notice on some specs actually implemented some functions on it, although it’s still unable to read. I set up the SysRescueUSB key but then i had to finish a support request on a Vista laptop. Could be worse, but Vista by itself is a problem for me: I cannot connect Vista laptops to my router directly, they kill it! I have to connect them through one of my laptops (my mother’s or mine) or through Yamato. I have no idea why. Okay no problem. I finished the cleanup, and the laptop was ready to go.

Today, I was woken up very early since I was to be at home by myself, which also called for a good morning of relaxing playing with the PlayStation… yeah sure. First my brother in law dropped by with my nephew to pick up some of his tools that were left here, then I finally cleared out some tasks for a job I have to do, which called for testing, after lunch.

But while I finish set up the stuff for this job I also decide to set up another side job I was commissioned, of which I’ll try to blog in another moment since it’s really interesting to me and I might actually release it as Free Software afterward. For this job, though, I need Windows, since it’ll have to run on Vista. I have an XP license (not OEM, thus not tied to a box) but it was set up to work on the laptop, since that was the most powerful box I had at the time, and Enterprise was not VT-X capable so I wouldn’t run it there virtually; now the laptop is no longer the most powerful machine at home, and I don’t care much about playing on XP, (I only have two games running there and they should work fine on Wine nowadays), so I wanted to move it out, reclaim the free space on the laptop, and install it on VirtualBox. Unfortunately as soon as VirtualBox starts, Xorg crashes, and it does not wake up the video card when it starts back.

Two hours of fiddlings later I get to find out:

  • gnome-settings-daemon, updated today, does not always start properly; no clue why yet;
  • SDL applications were killing my Xorg, I noticed this with tuxtype before, and the same happened with VirtualBox;
  • the reason why Xorg couldn’t wake up the videocard was the framebuffer; since I don’t even use the framebuffer when SSH is not working (I love serial consoles) but rather the laptop so I can have cut and paste, I just disabled it and I live happier now;
  • the Xorg crash was in the VidMode calls;
  • the Xorg crash was already reported as FreeDesktop bug #17431;
  • the Xorg crash was caused by SDL bundling its own X11 libraries !

So once again not following to the letter the policy that tells us to always use system libraries wasted more of my time than it should have. I guess this is life for you.

On the other hand, I need Mono for the commissioned work I talked above, but Mono in Portage is currently very badly present, since compnerd hasn’t bumped anything in quite some time. Today I opened a few bugs around for Gtk# for instance, and I hope I’ll be able to bump a few things in my overlay and force-feed them to Portage in a week or two.

On a different note, I start to have some hardware cravings, in particular I currently have no free USB port, no Ethernet cable and just one USB to serial adapter left, this is very suboptimal. I guess as soon as my job pays me I’ll be getting a self-powered USB hub so that at least I can replicate a few extra ports. I have a crimping tool for Ethernet cables but it does not do Cat5E cable, and I wanted to buy Cat5e if I was to buy more new cables…

Dualhead, 16:10 and XRandR

With my move to Gnome I decided to try out again the graphical login. I used to use standard console login before because KDM lacked too many features, and while for some time I kept using GDM, it just didn’t feel right. Unless I was going to just do some system administration, or testing PAM, the only command I was going to type was startx, followed by sudo shutdown -h once I was done.

To do so, I had to give up keychain, at least for inserting the private key’s passphrase. Instead of using that, I decided to change my PAM setup to use pam_ssh (and this is also what brought me to plan removal of pam_ssh_agent .. I just remembered I forgot to add that to the Gentoo Calendar! — done!), so that instead of typing my password and my SSH key passphrase, I just have to type in my passphrase at login and I’m done. The nice thing is that the standard Unix password is also accepted, so I can use that to take me out of the lock screen that Gnome applies when I walk away from the system, which is much shorter.

Again, I will probably put up a request for an electronic ID card next september and consider using a smartcard reader (I I wonder if I can use old, invalid, credit cards as smartcards too, once they are formatted).

So okay, I’ll write at another time about pam_ssh, it’s not what I’d like to write about right now.

With GDM I’m having one problem: my current setup is a dualhead, with a 16:10 monitor (and a 4:3) and using XRandR 1.2 (radeon driver). I have the screen disposition set up in my xorg.conf, but I’m not able to set the proper mode for the 16:10 monitor in the configuration file. If I set PreferredMode in xorg.conf, X11 refuses to start, without any apparent error either.

So for now I’m running at the session manager level two xrandr commands to set up properly the screens, but there is one problem: synergys does not seem to be expecting the geometry of the screens to change, so it still wraps my pointer out on the coordinates where it should have wrapped before the xrandr fixes.

I should probably see to try the latest masked version of xorg, and check if it works there. Although I think Synergy should have considered the case of changing screen layout. Maybe one day it will be rewritten using XCB and it will consider that problem too ;)

Oh yeah I should be writing about XCB too…

Fedora 9 and VirtualBox

For a job I have been hired to do now, I have the need to keep a virtual machine with the development environment. The reason for this is that there are a few quirks in that environment which caused me some headaches before.

As it’s not like the other virtual machine (on the laptop), requiring a perfect Windows support, I decided to go with VirtualBox again. Which by the way forces me to keep GCC 4.2 around. But oh well, that’s not important, is it?

The choice of distribution inside wasn’t difficult, I thought. I didn’t want to rebuild system on a vbox, no Gentoo. I avoided Debian and Debian-based, after the debacle about OpenSSL I won’t trust them easily. Yes I am picking on them because of that, it’s because it was a huge problem. While I found openSUSE nice to install on a computer last month, it didn’t suit well my needs I thought, so I decided to go with Fedora 9.

I used Fedora a couple of times before, it’s a nice development environment when I need something up quickly and cleanly. Unfortunately I found Fedora 9 a bit rough, more than I remembered.

I wasn’t planning on giving it Internet access at first, because of my strange network setup (I will make a schema as talking with Joshua made me think it’s pretty uncommon); but then the package manager refused to install me the kernel-devel package out of the DVD, it had to use the network. So I tried to configure the network with a different IP and netmask, but this didn’t work cleanly either, the network setting interface seemed to clash with NetworkManager. I admit I didn’t want to spend too much time looking for documentation, so I just created a “VBOX” entry on NetworkManager which I’m selecting at each boot.

After this was done, I updated all the packages as the update manager asked me to do, and tried to install the new kernel-devel. This was needed by the VirtualBox guest tools, which I wanted to install to have the “magic” mouse grab. But VirtualBox refused to do so, because Fedora 9 is shipping with a pre-release Xorg 1.5 that they don’t intend to support. Sigh.

I’m not blaming Fedora here. Lots of people blamed them for breaking compatibility with nVidia’s drivers, but they did give enough good reasons to use that particular Xorg version (I know I read a blog about this, but I don’t remember which Planet it was in, nor the title). What I’m surprised of is that VirtualBox, although being vastly opensourced, seems to keep the additions closed-sourced, which in turn cause a few problems.

Different Linux distributions have different setups, some might use different Xorg versions, other different kernel building methods, and I sincerely think the answer is not LSB. Interestingly, you can get the VMware mouse and video drivers directly from Xorg nowadays (although I admit I haven’t checked how well do they work), but you cannot get the VirtualBox equivalents.

If any Sun/ex-Innotek employee is reading me now, please consider freeing your guest additions! Then your problems with supporting different Linux distributions would be very much slimmed down: we could all package the drivers, so instead of having to connect the ISO image of the additions, mount it, install the kernel and Xorg development files, and compiling modules and drivers, the only required step would be for the distribution to identify VirtualBox like it was any other “standard” piece of real hardware.

I hope the serial device forwarding is working properly as I’ll need that too, and it did throw me a couple of errors since I started installing Fedora… I haven’t tried it yet though. I hope there are picocom packages for Fedora.

Again about .la files (or why should they be killed off sooner rather than later)

I’ve been working as an experiment on rewriting xclip to use XCB rather than Xlib. This is mostly because I always have been interested in XCB but I never had time to learn the internals too much.

To make my task easier I ended up using some funcitons that are not available in the currently-released version of xcb-util, the side-package of XCB that contains some higher-level functions that make it easier to replace Xlib.

Beside the fact that xcb-util still haven’t bumped its version, which makes it impossible to check for the right version with pkg-config, there is one interesting point in using the latest available version through the x11 overlay.

Letting alone some problems with being able to actually fetch and install the packages I need (Donnie, I’ll send you the patches later if I can polish them a bit), over the actual GIT tree there are a few patches applied, coming from Jamey Sharp (an XCB developer) from March 2008. These remove one library (libxcb-xlib) and change the locking method used to make Xlib use the same socket as XCB. These changes not only break ABI (without changing the soname, alas!) but also make it impossible to build the old libX11 against the new libxcb. Using the live version of libX11 (that is also patched to use the new hand-out mechanism) fixes this problem, but the result is a way bigger trouble.

First of all, this is a perfectly good example of what I said about preserve-libs. If you are not using --as-needed, and you had libX11 built with xcb USE flag enabled, you’ll have libxcb.so.1 links on almost all X-using binaries in your system; after rebuilding the new libxcb and libX11 (which respectively would install libxcb.so.2, in theory, and let libX11 link to that), all the binaries will have in their process space both the old and the new libxcb. With different ABIs. And that’s a huge problem on itself.

Then there is the other problem, that is related to the .la files I discussed a few months back. As a huge amount of KDE modules (and not limited to) linked to Xlib, they also had libxcb-xlib listed in their .la files dependencies. Which causes everything to fail linking with libtool as it’s looking for the missing libxcb-xlib.la file.

I suppose it’s time to spend time to get a script to fix this situation, but I admit I’m not much motivated at the moment. Especially since my system is pretty slow when it comes to rebuild stuff for testing, and my employer is not going to pay me anytime soon to allow me getting a newer box.

Once the script is available, it should probably be much much easier to get rid of .la files in ebuilds, as we could just say to the users to run the fixing script and be done with that..

But I admit I was planning on doing some different things in the next days, I had little time for myself lately to begin with, and I’m following way too many things at once. Sigh.

Licenza Creative CommonsThis work by Diego Elio Pettenò is licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License.
Based on a work at flameeyes.blog.

My thoughts about Synergy

I was suggested more than once lately, especially after my posts with multiseat, to try out Synergy. Well, I did :)

It’s quite an interesting program, and it actually saves me from having to use two mouse at once every time. Too bad I needed a mouse anyway to get the second seat, or I would have saved quite some money, too.

There are a few problems with it, though, for instance the server crashes from time to time, stopping access from the clients.

It’s unfortunate that the project development has slowed down, as it would be quite an interesting thing. Having better support for OSX for instance would be nice, as it is, part of my keyboard does not work on the laptop because there are keys that are NOT on the laptop.

One way to achieve better integration would be, I suppose, to make it act as an input driver on OSX. Using the same protocol, but rather than having a daemon, having an input driver that “installs” its own keyboard and mouse. It would probably then allow to use as many keys as the server has.

A similar piece of software could be done under X11: an Xorg driver that handles the input as a virtual event. With such a software I could easily get rid of the keyboard and mouse that I reserved for the extra seat and leave it as a virtual device.

If only Xorg would be more easily shared between instances (less use of .data.rel for instance) it would be quite interesting to use the monitors with three separate instances; this way it would handle dpms differently on a per-monitor basis, and shut down the extra monitors when not needed; as it is unless I do it on my own, the monitor at my left is always on, as it’s handled by the same session as the central one.

Well, if anybody wants to start working on it, it would be appreciated :)

Dual seat need development

So yesterday I started fiddling with bringing up a dual seat system. It’s not really bad as it is, it’s actually quite interesting to have it working. I’ve also been suggested to try Synergy, which could solve also the need for two keyboards, bringing a similar effect than xinerama even if ran with more than one X instances, and I probably will try it out in the next weeks.

I’ve been thinking a lot about dual seat lately. With today’s CPU power, with multicore systems, and high memory, most users are going to waste CPU power. Beside the users of Vista that need a last-model system just to make the desktop appear, graphic artists, developers and gamers use their CPU power. Most home and office users have a false need for more powerful boxes: browsing the web, writing letters, downloading photos from a camera are all tasks that require very little CPU power and not so much memory.

Think for instance of a family with two kids, both of which want their own computer: why not setting up a single computer with two seats? Then both kids can do what they want with the computer (or almost) with just one more monitor, keyboard and mouse, which is a limited cost compared to a whole new computer. Now of course doing this with Windows is quite… impossible, I suppose, so the kids will have to use Linux, but that’s not the point anyway, right?

Another place where this could certainly be useful is schools. I didn’t know it, but reading the Wikipedia article on Multi-seat, this is actually being used in Paraná. This is quite an interesting fact, especially for people like me who are concerned with the waste of money in the educational system, like I wrote (in Italian) yesterday .

Education is not free, there is a cost tied to that, but education is what can improve society. Better education helps people on the long run, if it’s proper. In Italy for instance I have a lot of reserves over the working state of universities, especially after seeing the mess I actually tried to get into myself.

Computers can improve the quality of education, but they don’t come free; even when they seem to come free as they are provided by a manufacturer, they have a cost behind them. Free Software can cut the cost on software (license-wise), but it can’t cut the cost of hardware up to a certain point (you can avoid the requirement for newer systems that Vista puts on everybody), alone. Multiseat can cut this cost as you can easily have four students working with a single computer. Even in a computer science class like I had in my high school, the power of the computers could easily divided in four without any problem with the users.

Unfortunately multiseat is not yet easy to handle in modern Linux systems. While it’s certainly possible, and thanks to modern hardware like multi-head videocards and USB keyboards and mouse there is no need for strange hardware anymore, the software support for multiseat seems to me quite lacking.

The only way I could get it to work on my system was to use evdev for the keyboards. But latest release of evdev didn’t like me to tell it to use a Device, nor it liked the use of Phys. I had to take the latest GIT version, and that worked, but still required me not to change the order of connection of the keyboards and mice. Also it’s quite an incomplete support what we have now, for instance I can’t get F13 to F19 to work on evdev without using xmodmap.

Input hotplug is a pretty nice need for modern desktops, but it will be pointless or even broken for multi-seat arrangements. I’m afraid of what might happen when Xorg will relay on that.

But even without going into Xorg itself, there is need for better support for multiseat in software, by for instance understanding that even if there is usually just one instance of a software per-user, there might be more than one user on the system logged in at once, and so it makes sense to be able to share as many pages as possible by using properly .rodata and similar.

I think it would be nice if there was a more focused look into this kind of possibilities in the Free Software communities. For instance it would be nice to provide better tools to developers to even test multiseat without having to create one in true hardware. Sun: you bought InnoTek and are now taking care of VirtualBox. Give us a properly-working virtualised environment with two or more video cards, so that developers can actually test their code on multiseat, that might be good for your karma too :)

I think I’m already working toward this goal myself, even if I didn’t understand that before. My work toward reducing Copy-on-Write pages will make better use of memory in multiseat environments, and I’ll continue with it for a long time.

I’ve seen there are similar work in progress for improving support to multiple video cards. It’s also a piece of the puzzle. Making better use of disk space is also an important task. Even if the cost of disk space is falling down, employing it in the right way will reduce the cost on education, too.

Don’t ask me how I started being so concerned with education, probably it depends on the fact I see a lot of bad things happening that could be solved even just with a bit more knowledge of how processes work…

Setting up a dual-seat system

So I was unable to get all the three monitors working on a single X instance. The 4260 size was too much for X to handle properly, so I decided that the best way to handle this is to get two seats working.

Using a multi-seat system seems like a totally nerd thing, but I would think that with modern multicore CPUs a multiseat system might replace well two or more boxes, if configured properly, in offices and school. But I’ll see to dig deeper into that when I have tried using it for a while.

It might be wroth writing down a few comments about the way I ended up with the video card I’m running now: my 3D Blaster Banshee had the display totally corrupt, I’m still not sure if it’s the video card being broken or an incompatibility between it and the ATi AGP card; the Matrox Mystique didn’t arrive to 1280×1024, I was able to get it at 1024×768 but it’s a bit… too tiny for me, there was not enough video ram (2MB); I ended up trying with an S3 ViRGE just because it looked packed with video ram, and seems like I was right, it supports 1280×1024 just fine… if it wasn’t for the refresh rate. I do hope the problem is with the “ugly pattern” we all know from Xorg, I’ll check better later to see if it works fine with dwm, if it doesn’t, I’ll try to see how it works at 256 colours….

It is strange to see how it’s difficult to find modern mainboards with more than one PCI-E x16 slot, and 16GB of RAM. I decided to get a quad-core for my next box with 16GB of RAM, with the current jobs I’m taking it should be possible for me to get it before June, but I’ll still have to deal with PCI video cards, for that reason (as for why 16GB of RAM… should make it less a pain to deal with repeated compilation of C++ code… and I want to use a few virtual machines); as far as I can see there’s no way to get, with Xorg, two seats working on the same videocard.

By the way, if you follow the Wiki, then you’ll probably see it does not work properly: evdev 1.1 does not respect Phys, evdev 1.2 does not open the devices at all, evdev from GIT works better, but you have to specify the event device to use (nasty, but works perfectly fine as you can symlink stuff around with udev).

Talking about udev, the default /dev/input/by-id symlink are completely useless in my system. The reason is quite easy: I have an Apple Aluminium keyboard (I can’t find anything better to write on!), a Logitech LX700 Cordless Desktop, and since yesterday an MX Revolution mouse; each of these peripherals creates two input device in the kernel (don’t ask me why): the first has one device for the basic keys, plus an extra one for extended keys (like fn); the second has a device for the standard keyboard, plus multimedia keys, and one for the mouse, plus all the extra keys as mouse’s buttons; the third has one device for the mouse, plus one for the extra buttons).

As /dev/input/by-id uses the name and the type of the devices, the Apple keyboard overwrites the symlink by itself, as it obviously has the same name, and has two keyboard devices. The Logitech peripherals instead work quite nicely if they are alone, but as both of them have as internal USB name “Logitech Receiver”, and both have one keyboard and one mouse, … I leave to you guess what happens.

See Greg? This is where usb.ids comes out useful ;)

Anyway, later on today I’ll blog more about the dual-seat system, right now I have some documentation to update and some work to do for my job ;)