Texts on Tiago Vignatti

Accessibility and PDF documents

Wed, 04 Mar 2026 10:00:00 -0300

Accessibility
#

When we think of accessibility, we tend to picture it as something designed for a small minority. The reality is much broader: 16% of the world’s population — 1.3 billion people — live with a significant disability¹. In Brazil alone, where I live, that means around 14.4 million people report some form of disability². And those numbers capture only permanent disabilities.

From Chromium to Community

Fri, 15 Aug 2025 11:28:03 -0300

Co-op principles for everyone.

Organizações Sustentáveis: Lições da Igalia

Wed, 09 Apr 2025 11:05:16 -0300

Princípios para qualquer organização.

Sustainable Organizations: Lessons from Igalia

Wed, 02 Apr 2025 14:52:37 -0300

Principles for any organization.

Using Chromium for Building Apps

Wed, 04 Dec 2024 10:36:37 -0300

Beyond the browser.

Good fortune 복

Tue, 19 Nov 2024 12:00:28 -0300

Chromium and friends in Seoul.

Short blog post from Madrid's bus

Tue, 21 Jun 2022 00:34:34 +0200

Wildfires and Igalia’s 20th.

My Startup Dream

Fri, 06 Aug 2021 00:00:00 +0000

Skateboards to VR.

Stars Aligned

Mon, 08 Mar 2021 22:04:11 -0300

Wedding, baby, and grandma’s birthday.

Quilombo

Tue, 23 Feb 2021 21:07:43 -0300

A beach.

Oculus Quest

Mon, 15 Oct 2018 17:21:23 +0000

It won’t run Rift apps.

Chromium Ozone-GBM explained

Thu, 09 Oct 2014 16:46:29 +0000

About a year ago Ozone platform abstraction layer started to take its shape in Chromium and we were excited how easily we could support Wayland platform using it. Everything went great and we helped a few Chromium targets like Crosswalk to debut in the Tizen ecosystem for example. More recently, different Ozone platforms have been implemented and only now it’s becoming evident the significance of Ozone for Chromium Linux, generally speaking.

[video] Chromium Browser on Wayland

Fri, 07 Feb 2014 09:00:33 +0000

Some state-of-the-art progress of the project we’re proudly working with:

https://www.youtube.com/watch?v=EJB2pznc6iY

developing Chromium on Wayland

Mon, 07 Oct 2013 14:42:17 +0000

A few weeks ago we released Ozone-Wayland and now we’d like to detail for you the development process and strategy behind it… ah, and the title is not developing Chromium, the browser; it’s developing Chromium,** the project**! You will understand why next.

Welcome to Chromium's Ozone-Wayland

Wed, 18 Sep 2013 13:34:24 +0000

The following message was sent out this morning – I’m copying it here and attaching a cute screenshot of my desktop :)

Ozone is a set of C++ classes in Chromium for abstracting different window systems on Linux. It provides abstraction for the construction of accelerated surfaces underlying Aura UI framework, input devices assignment and event handling.

UI customization on Wayland

Tue, 05 Mar 2013 15:00:00 +0000

Let’s forget for a second about video drivers, whether it has acceleration or not, and all the related issues with hardware support on Wayland. This is all solved. Let’s talk about the user interface (UI) and ways to customize it all over the computing continuum – from phones, tablets and TV box to desktop PCs, Invehicle Infotainment (IVI), aeroplane systems, among others.

the damn small Wayland API

Wed, 17 Oct 2012 13:15:38 +0000

Wayland 1.0 release is knocking the door and people keep asking “why Wayland if we got X already”, or things like performance, memory consumption, power savings and other kind of advantages on having Wayland instead X. Those are very important points to consider, of course, but for one individual actually programming the graphics system the answer should be straightforward: Wayland API is damn small.

X on Wayland

Wed, 13 Jun 2012 14:01:32 +0000

A rather cool feature on Weston compositor is xwayland, to support X11 native applications on Wayland. It’s a quite important feature because gives the compatibility with the “old” windowing system, so say you have an application written on Motif/Xt or even something more “fancy” like a Web browser all tied with GTK2 and whatever dependency, then you better not bother yourself re-writing it to native Wayland or porting to a modern toolkit – it should just work seamlessly on it. Hence, X on Wayland fits pretty well with our overall transition plan.

starting on Wayland development

Wed, 18 Jan 2012 13:53:43 +0000

Do you wanna contribute to a funky open-source project? Are you tired of your nerdy and boring community of developers? Are you the one that wants to get rid of X because it’s a giant, old and fat dinosaur in your system? :) Cool, I have a project to solve your problems!

Qt on wayland: howto

Mon, 19 Dec 2011 23:31:29 +0000

To run Qt applications on Wayland is fairly simple nowadays. Thank to Qt developers, they are following up quite well our last changes on Wayland protocol and updating accordingly on Qt5 code base – by the way, the fresh and just released Qt 4.8 does not ship the latest protocol additions, so that’s not the one I’m referring.

... if I didn't say

Thu, 22 Sep 2011 15:55:54 +0000

Hello Intel Finland :) Here I am now; four months already at OTC big team.

X characterization for MeeGo

Wed, 20 Apr 2011 13:35:44 +0000

Actually this is not a big news but it’s nice to see on practice X being used on the advanced age :) Here I’ve played with some UI configuration settings, browsed for while, toyed with facebook, opened some photos in the viewer and etc, all for about 5 minutes:

X Census (for 1.10)

Mon, 28 Feb 2011 20:31:05 +0000

Following is the census of 1.10 window for all X infrastructure - raw numbers here. I did it in a similar way as the previous version. Worth to mention that there’s almost no relation between the cycles of development from each of the components listed below, which can lead to some misunderstanding. Anyway, still a nice indicative to see and evaluate how the free desktop community behaved.

X.Org Foundation elections

Fri, 18 Feb 2011 13:31:43 +0000

I am a candidate for the elections 2011 of the board of directors :) Following are my answers based on the questionnaire formulated by the members. You can check other candidates answers here.

late Christmas gift: freedesktop's Xorg for MeeGo

Wed, 29 Dec 2010 19:46:07 +0000

Moikka.

If you follow here [0] you will see a set of Debian packages that Graphics team at Nokia are continuously working to deploy a X11 implementation for MeeGo-Harmattan, where we target embedded systems only. Feel free to use it!

X Census (for 1.9)

Thu, 02 Sep 2010 13:41:11 +0000

Topic’s name is a funny (and friendly) devotion to GNOME Census. So let’s take a look at some numbers from the time Xorg 1.9 was in development - raw data is here.

Would be unfair to measure only the work that happened e.g. in X server or in the drivers being developed and come up with the statistics about “who developed X”. X and X development community are quite extensive and don’t concern only “graphics” related, i.e., pixel information that appears on your display screen. This is a very common mistake.

Xorg server 1.9 minimal

Wed, 18 Aug 2010 15:22:26 +0000

That’s what I’m using for MeeGo now. Autoconf parameters, theeere we go:

–disable-static –disable-aiglx –disable-config-dbus –disable-config-hal –disable-dbe –disable-dga –disable-dpms –disable-dri –disable-glx –disable-glx-tls –disable-int10-module –disable-ipv6 –disable-screensaver –disable-secure-rpc –disable-tcp-transport –disable-vbe –disable-vgahw –disable-xdm-auth-1 –disable-xinerama –disable-xwin –disable-xaa –disable-xace –disable-xdmcp –disable-xf86vidmode –disable-xfree86-utils –disable-xnest –disable-xvmc –disable-libdrm –enable-config-udev –enable-dri2 –enable-null-root-cursor –enable-record –enable-unit-tests –enable-visibility –enable-xorg –with-sha1=libsha1

Linux Graphics for Small Devices at FISL

Fri, 30 Jul 2010 16:38:58 +0000

Last week I’ve been in Brazil at 11th International Free Software Forum (FISL) talking about Linux Graphics for Small Devices*. I tried to cover a bit of everything that I learned in the world I’ve been immersed in some near past - I guess there aren’t many news for freedesktopers though. Anyway, everyone is very welcome to give any kind of feedback and comment on it. Just follow here.

Attracting reviewers in your patch series

Mon, 12 Jul 2010 12:56:01 +0000

Usually faster the number of commits, faster the development process. But development without strict reviewing doesn’t guarantee quality on the code. Unfortunately, rarely you will see people willing or even just being able to review the changes you are proposing. Attract reviewers is hard!

adopt a child and make multi-card work on Linux

Wed, 23 Jun 2010 15:12:11 +0000

Previously, the message was for toolkit, now it targets new upcoming developers… okay, if I’d be offensive I could say it targets vendor distributions which care for desktop on Linux :)

Toolkit, please: Xlib -> XCB

Tue, 15 Jun 2010 15:24:11 +0000

We all know since 2006 (?) that the world is turning to use XCB instead Xlib as the interface between X clients and the server. The advantages of using XCB is well know but, even so, it’s being adopted very slowly for some reason - for instance no toolkits yet ported it. If this serves as a motivation, Alan got a really nice measurements porting a simple X app.

Scrutinizing X memory, part 2: what's taking all that memory?

Thu, 25 Mar 2010 18:01:10 +0000

So here goes some statistics of the Xorg process running. All the informations were fetch from /proc/pidof Xorg/{smaps, status}. I used also a script found on the Web to parse and organize these informations; Mikhail Gusarov has extended this script to show a very useful output.

Scrutinizing X Memory, part 1: overview

Thu, 25 Mar 2010 17:58:47 +0000

This series of documents explore how the memory is used by the Xorg server. They aim to eventually shrinks the memory footprint of the server and its related components, like X clients, modules being loaded and drivers. Embedded devices with constrained resources are the main focus here. All texts are mostly based on x86 and ARM architectures, under Linux 2.6.33 with Xorg from upstream.

Customization and true modularization of Xorg

Sat, 23 Jan 2010 17:20:25 +0000

For the first time in life, Xorg is being used in a single platform and for a given device only (other devices have used an X11 implementation but using other non-canonical servers, such kdrive’s based - Tiny-X).

New blog interface

Tue, 29 Dec 2009 01:42:19 +0000

I like UI and I’m not gay.

Some time ago someone posted a comment, complaining about the white fonts over the dark background in my blog, which makes the read be difficult. The guy teased me, recommending an ironic page where shows how hard is to read texts like this. He was right…

Xorg: What is it, and what does it mean?

Sat, 26 Dec 2009 18:36:49 +0000

Just a thought is this something that should be deleted? This seems to be using about 7% of my RAM

I don’t have words for it.

my dear diary... (some not-so-old memories)

Mon, 09 Nov 2009 01:47:17 +0000

Portland, OR

I was so proud for the forth time be part of the X crew, this time in Portland. Really amazing the city. I had the opportunity to play tourist and visit some nice places.

multiseat with multiple X servers (or "the right way")

Fri, 24 Jul 2009 13:56:33 +0000

So last week I posted on lkml an old patch that we were carrying for a long time in the Linux community. It basically brings the multiple (old) video cards functionally again on Linux and X server (and this time doing on the right and beauty way). For the people that was following multiseat implementations, this is a HUGE step: we will finally be able to discard the old and ugly hack (a mix of Xorg, several Xephyr servers + evdev) and and go to a clean way, starting multiple X servers in parallel. Cool! Well, not that much, because it might take some time to be in your beloved distribution :)

Nokia, FI...

Fri, 12 Jun 2009 07:06:59 +0000

… here I’am :)

personal news

Sun, 17 May 2009 20:22:49 +0000

Being quick about my last months: finished my Master course, moving to Helsinki tomorrow (!), got my first real job. Yessh, three great steps in my crazy life and I’m very happy with it! Hope to stay closer with the desktop communities again ;)

Cursor's update inside kernel only

Wed, 14 Jan 2009 22:48:44 +0000

One thing that I learned with open communities is when you send a proposal idea and no one replies. This seems to be odd at first but it isn’t. If you did something strange or wrong then at least someone will reply. OTOH if you did something that can be promiser and no one objects, then great! 99% that you did something interesting :)

multiseat - documentation and references

Fri, 09 Jan 2009 04:25:51 +0000

Trying to put some order with all the multiseat documentation found on Web, today I updated the following:

Multiseat’s article, in X.Org Foundation wiki: http://wiki.x.org/wiki/Development/Documentation/Multiseat

Multiseat’s history, in Wikipedia: http://en.wikipedia.org/wiki/Multiseat#History

So if you are trying to setup or help in development, probably the foundation’s wiki has the most up to date and centralized references. Also, please, if you have more helpful information, don’t be afraid to update the wikis. Our future grandsons will be thankful :)

multiseat - roadmap

Tue, 23 Sep 2008 04:52:08 +0000

This week our laboratory at university released the MDM utility to ease the process of installation and configuration of a multiseat box. The idea is that the end-user should not use some boring and hard howtos anymore to deploy it. Just installing a distro package must be enough now. Try it, use it, report the bugs and send the patches! :)

Parallel events (panic) with X

Mon, 18 Aug 2008 22:02:16 +0000

Unfortunately that model which I described some weeks ago to put the input event delivery of the X server in a separate thread wouldn’t be an advantage. I precipitated myself thinking that it could be feasible. Sorry :(

Priorities and scheduling hints for X server threads

Thu, 07 Aug 2008 23:33:57 +0000

Input events routed through another thread/process can have bad effects on latency because we can’t guarantee that it will get scheduled at the right moment. Although this is hard to see happening with the current X server threaded implementation, we must design something to avoid it. One way to improve the responsiveness is to give a high priority to the input thread and also adjust the CPU scheduling. (Note that this will not avoid problems related with page faults which usually happen in the X input flow.)

keep it going...

Thu, 07 Aug 2008 23:22:27 +0000

Given that GSoC ‘08 is getting close to the end, strategy number 2 showed more feasible to proceed my work. Strategy #3 would be a lot of fun but would imply a hell massive codification as well (also a little out of our scope). Unfortunately no-no for now.

Improving input latency

Wed, 30 Jul 2008 01:09:31 +0000

GSoC summary #1 - July 29

The current implementation of X Window System relies in a signal scheme to manage the input event coming from hardware devices. This scheme frequently get blocked when lot of IO is occurring (for instance, when the process is swapping in/out). Get blocked means for instance a jumping cursor on the screen and in GUI is always desirable to prioritize the system responsiveness for end users. The human/computer interface should be smooth and this is the most user visible aspect of a system.

cursor handling and updates inside DRM

Thu, 10 Jul 2008 07:03:49 +0000

The current DRM kernel modesetting tree is already taking care to update the cursor registers and paint it to the screen. Very cool [0].

What I’ve done today is a shortcut between the kernel input layer and DRM to update the cursor directly on screen without the X server be notified always. Of course, a lot of issues raised up together. So let’s try to delegates the tasks again.

to thread the X server (?)

Tue, 17 Jun 2008 23:39:53 +0000

I really don’t like to read large blog posts. Anyway…

What I did so far is a separated thread that takes care only the injection stage on the X server queue. Who is interested with the results, please read some past posts in my blog. It is currently in a very good shape (synced with post-mpx merge, all input devices are inside the thread and etc). The implementation looks like this: thread #1 deals with - injection of input events from devices thread #2 deals with - processing of input events to clients - requests from known clients (rendering things) - new client that tries to connect (pretty easy to do)

fakemouse -- a driver that emulates a mouse

Wed, 28 May 2008 02:36:09 +0000

For my SoC project I need some mechanism to evaluate the improvement of the input thread inside X. So I wrote a simple kernel driver that emulates the mouse device moving and emitting bits of a simple pattern. I don’t know if something like this already exists or if there are other ways to do it, but the fact is that the solution I thought took me only few hours between the moment that I imagined, collected some ideas on the Web and implemented it.

Google Summer of Code 2008

Tue, 29 Apr 2008 21:31:27 +0000

I’m very happy to say that I was selected again to work on Google Summer of Code with X.Org Foundation. Daniel will be my mentor again. Thanks Google. Thanks X.Org!

In the last year we did a nice work separating the input event generation code of the X server into a different thread. We saw some performance improvement there specially because the implementation is not using signals anymore to wake up the server when some device emits an event. The reason why is that when a process is in the uninterruptible sleep (D state) signals are delayed and the mouse cursor lags.

Traversing X11 clients behind NAT (or X11 end-to-end connectivity)

Fri, 21 Mar 2008 20:29:33 +0000

I was thinking how we could make remotely X clients totally connective with the server when both are behind a NAT/firewall.

We can imagine one big motivation to do this: a scenario where someone using his thin and poor machine wants to use the resources of some “fat” machines which he simply doesn’t know where they are seated. Those fat machines could be arranged through a P2P network of “X11 pool of resources” and the list of machines displayed to the user select his desired one (e.g. with minor lag/load). Someone more capitalist than me could go further and imagine a provider selling X11 resources to mobile devices. Or just open your home machine’s web browser in any place of the world. Well, the field of applications would be huge.

VgaArbiter wiki

Mon, 25 Feb 2008 21:59:17 +0000

Today, Paulo Zanoni help me to put in a shape the VgaArbiter wiki page. The primary intention of that page is to bring more developers in that project and some users++ who could also help testing. Feedback is very welcome. Here is the link.

Benchmarking it all

Thu, 21 Feb 2008 23:53:39 +0000

After a long journey I come back in this… So I did a set of benchmarks to evaluate the VGA arbitration versus the RAC usage. My goal is to evaluate the performance difference of a multi-head/multi-card environment, i.e., an Xorg using the RAC to another using the arbitration.

VGA arbiter: removing RAC

Thu, 20 Dec 2007 01:18:39 +0000

The Resource Access Control inside Xorg is the guy responsible to take care of the various resources of memory and to share them in a wise manner when two or more graphics devices are active (think multi-head). As an alternative from RAC we can rely on VGA arbiter. So me and Paulo Zanoni spent the last days implementing “the glue” of Xorg to use the arbiter code with this purpose.

The VGA arbiter

Fri, 23 Nov 2007 15:26:39 +0000

So we finally have a working code to do the arbitration of the VGA legacy instructions. The code is separated in three pieces: vgaarb module [0], which is the arbiter itself inside Linux; the libvgaaccess [1], a set of user space functions to access the arbiter; and xf86VGAarbiter [2], the implementation of the library inside Xorg.

Realistic :(

Fri, 09 Nov 2007 19:43:36 +0000

MacOSX -> GNU/Linux

Wed, 26 Sep 2007 04:06:33 +0000

I used a part of the money that I earned on the SoC 2007 to buy a laptop to me. My university friends found a good price of a MacBook and we went to the shop in a total of 6 people (!) to buy this laptop trying to get some discount. It cost R$ 3400 (about USD 1800), a very cheap value to the Brazil standards.

Xorg input thread - summary or something #3

Tue, 28 Aug 2007 02:32:41 +0000

Not so much, but here are the news:

 * For the final evaluation period on the Summer of Code, Daniel suggest me to start my [own X server tree](http://gitweb.freedesktop.org/?p=users/vignatti/xserver.git;a=summary). So I'm maintaining this one with the last bits of the X server input thread implementation and always trying to keep all the things up to date with the upstream tree. Everyone is very welcome to test it and report me the few - I expect - bugs.
 * The last new regarding the thread implementation is that we're unfortunately dealing with **critical sections** inside the X event queue (mi/mieq.c), so mutex is needed there (just to note: currently, mutex is only implemented using pthread (X11/Xthreads.h), so we also need implement something that is pthread-independent). Probably can exist other pieces of code that might be in an unpredictable way resulting some race conditions (didn't note anything strange yet!).
 * I finally managed how to implement the page fault notifier without any patch inside the kernel. The read_cr2() can be called directly since the page fault notifier runs with interrupts disabled. The implementation can be found [here](http://web.inf.ufpr.br/vignatti/code/page_fault_notifier.c).

mlock()'ing adventure

Fri, 10 Aug 2007 22:30:07 +0000

It’s being a great adventure to lock the X input thread on the memory. I’m touching a lot of things that I’d never imagined before :)

To trace the pages that are faulting when I move the device pointer I’m using my own ultra mega super kernel’s page fault notifier. It’s very simple, but as the things are not always perfect, it needs a little patch in the kernel.

Page fault notifier

Fri, 27 Jul 2007 05:24:05 +0000

This week I tried to lock in the physical memory the Xorg’s input code using mlock(). To do this I traced the code minutely and locked all the text and data related to input. I didn’t get success. The mouse still lags when the system is paging (you might remember that with mlockall() all worked wonderful except that it eats much memory). So what might be happening is that something is not locked yet. To guarantee it I searched for a user-space tool that traces page fault. I only found the ’truss’ command on Solaris. Linux (my OS) doesn’t provide no one (‘strace’ don’t do this).

Xorg input thread - summary or something #2

Wed, 18 Jul 2007 02:14:13 +0000

In the last week, I did some cool experiments to see the effects of the D state acting on the X server process when I start it with and without the input thread and always mlock’ing it.

Xorg input thread - summary or something

Fri, 06 Jul 2007 03:13:09 +0000

This mail that I’ve sent to xorg mailing list tells the current state of my project.

cut here -

Hi guys.

As you might noted here [1], my GSoC’s project is to do a separate mouse thread for the X server. Now, I’m really stucked with it and I need some good ideas from you before go to the next steps.

Moving the mouse handling code into a separate thread

Sat, 16 Jun 2007 19:12:23 +0000

(In a puny attempt to write my SoC project progress to my mentor, I decided to expand it and share my thoughts with you)

Today, we have two methods to register the pointer devices on Xorg server: (1) under SIGIO and (2) put they fd on EnableDevices set. There is also the silken mouse concept, which means updates fired during sigio handler (in the case of hw cursor).

multiseat input hotplug

Sat, 02 Jun 2007 04:34:00 +0000

This week I spent a good time trying to understand the new input hotplug of devices on X and liked a lot. With this new subsystem the multiseat’s life will becomes easier. I’ll briefly explain here to you.

Google Summer of Code 2007

Wed, 02 May 2007 04:11:17 +0000

Certainly, my great new is that I was accepted as a student of X.Org Foundation sponsored by Google, on Summer of Code 2007. The project’s name is Moving the mouse handling code into a separate thread and in this link you can see what does this mean specifically.

FISL8

Wed, 02 May 2007 04:02:57 +0000

Here is the presentation I’ve given on 8th International Free Software Forum, at Porto Alegre. My first (really) public talk was really cool and I’ll show to you the video/photos when the organizers get it done.

The conception and the future of multiseat...

Tue, 10 Apr 2007 03:27:36 +0000

…this is the subject of my talk which will be held at FISL (International Free Software Forum) on this saturday, April 14th. I’ll post the feedbacks here.

X server semantics - number of users per server

Thu, 29 Mar 2007 03:26:39 +0000

Here is mail that I sent to xorg list a week ago. No one replied it :(

On IRC I talked with some developers and asked why they didn’t said nothing about my comments and the answer summarized was that no one is really interested on multiseat (well, at least on first world countries). Strangely, it really give me a good perspective and motivation to keep the work :)

X Address Translation

Sat, 24 Feb 2007 16:59:28 +0000

MPX brought to us a new idea of multiseat system.

Xat is an application that serves as an intermediary between the X clients and a multiheaded X server. Xat deceives its clients which have the impression that the server has only one head. The objective is that each head behaves like several distinct X servers. We can imagine a scenario where we have a xserver on display :1 with four screens (:1.0, :1.1, :1.2 and :1.3). After Xat being connected we have four displays (:2, :3, :4 and :5) and just one screen per display.

Multiseat state on Linux

Fri, 23 Feb 2007 03:50:18 +0000

For some reason multiseat doesn’t call much attention in countries that are not of the third world. I can be radical, but in my humble opinion there is no reason to not apply this model of computation in certain types of environment (I’m talking about kiosks, Internet cafe, office, schools, etc). The money saved is enormous, and this is only one of the advantages that I am enumerating here.

Hello world!

Sun, 11 Feb 2007 04:12:56 +0000

This is my first post and even my first blog. Well, the blog’s intention is to bring in evidence my interests about linux (and maybe music).