Watch out for kernel >= 3.0 power saving regressions…

November 30th, 2011 ntavares Posted in en_US, fedora, linux driver, performance, ubuntu No Comments »

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I was reading Phoronix comprehensive tests about recent power saving regressions - specifically important for laptops -, and would like to point out this to everyone, since, according to the article, it is not receiving much attention from kernel maintainers. As you know, I recently installed a Sony Vaio and an HP G62. Just to give an idea of what I’m talking about, have a look at their chart:

Phoronix Tests on power saving regressions

Also worth mentioning are the Intel graphics tuning options. I’m currently running these on both computers (as both have an i915 card), and yet didn’t find any problem…?

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Sony Vaio Z21X9E/B (CEP) and Fedora 15 (x86_64)

November 26th, 2011 ntavares Posted in dri, en_US, fedora, hardware, linux driver No Comments »

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Well, I’m one of the recent owners of a Sony Vaio VPC Z21X9E - who the heck is giving these brand model names at Sony?? - so, as everyone does when they get a new computer, I went to install my operating system - Linux. And, despite having said that it would probably not be Fedora again, well….. it was. And, yes, I was still using a 2-year-old distribution…


It worths mentioning that this laptop does not have a CD-ROM drive, so you either plug in an external one, use an USB pen or just kickstart it.

You might want to pass the following options on installation if you’re getting a blank screen:


If you want to preserve the Windows installation you will probably have to resize the “big” partition manually: I couldn’t get anaconda, nor Ubuntu installer, nor SuSE’s, so in the end, I gave up and went using the resizentfs tools.

Also, if you plan to wipe off the Windows partitions completely, you might want to try to tune the disk first by aligning the SSD. I didn’t: I was hungry for having it installed, and I already spent much time trying to install Linux without blowing Windows (it may become handy to debug some USB… :-)



Ethernet (Wired)

Although the Ethernet NIC was correctly detected, the base kernel driver r8169 had some stability problems. My first yum update brought kernel with the problem fixed. But it worths mentioning that first I had installed the Realtek’s official driver (donwload link) and it performed pretty well.

If you’re dealing with recent kernels, you may have noticed about Consistent Network Device Naming. Well, in short, I don’t like it :) So I told udev to get my ‘eth0′ back - can you imagine? It was called p3p1! :)

cat > /etc/udev/rules.d/80-compatibility-net.rules << EOF
# PCI device 0×10ec:0×8168 (r8169)
SUBSYSTEM==”net”, ACTION==”add”, DRIVERS==”?*”, ATTR{address}==”54:42:49:97:75:22″, ATTR{dev_id}==”0×0″, ATTR{type}==”1″, KERNEL==”eth*”, NAME=”eth0″

This is a two line file (first line is a comment), but Wordpress breaks it.


Although the wireless card (Intel Corporation Centrino Advanced-N 6230) was detected, the driver iwlagn needs firmware (you’ll notice that on ‘dmesg’):

yum install iwl6000g2b-firmware.noarch

Broadband internal modem (Gobi 3000)

I’m still wandering around on a good approach to this one. Many many info scattered around the web, with different results, with different models. For now, let me just reference to the Gobi drivers project page. I’ll get back on this as soon as I have something similar to an understandable approach.

Touchpad / Clickpad

You will quickly notice that the touchpad (actually, a Clickpad, I learned) will misbehave, leading to cursor jumps when you try to click, ignoring drag&drop, etc. It seems the synaptics driver is pending some clickpad awareness changes - for a long time now, I must say - and that’s why you will find the problem solved in (and by) many (other) distributions. Not in Fedora, though, at least in this case. In Bugzilla #590835, comment35, thanks to Alexander Gryanko, you will find a source RPM for a workaround. After recompiling and installing over your current xorg-x11-drv-synaptics driver, the clickpad won’t perform as well as in Windows, yet, but it will fix the annoying pointer-jump and will allow you to drag&drop and select text, which was impossible.

I’ve also read about using “i8042.nomux=1″ as kernel arguments, or Sony Jogdial overlapping the default touchpad (noticeable on the logs) but didn’t go that way. I’d like to hear from your experience about this, though.

Also, installing gpointing-device-settings might become handy later on…

yum install gpointing-device-settings

Keyboard Fn keys

They all seem to perform well, except for brightness control. I’ve seen many people complaining about this. Loading the sony_laptop module seems to do the trick.

modprobe sony_laptop


While you had to run the installation without modesetting, after the forementioned update (to kernel, the system now runs with modesetting, thus giving you the graphical boot.

Other hardware

  • Webcam - out of the box;
  • Audio - out of the box;


Frequently used applications

I found a lot of good suggestions here, although I always go installing the software along the way, as I need it. So this section is mainly targetting some special care needed for specific apps.


I like to (I actually have to) use both a legacy most stable version (1.6x) and a most updated stable version (1.7.x) due to professional reasons, so I like to have alternatives properly setup so I can switch between them easily. This is something that the Java RPM distribution should be doing automatically (for some years now), but they still don’t:

alternatives –install /usr/bin/javaws javaws /usr/java/default/bin/javaws 10
alternatives –install /usr/bin/java java /usr/java/default/bin/java 10
alternatives –config java
rm /usr/java/default
ln -s /usr/java/jdk1.6.0_29 /usr/java/default

Tweaking the environment

Fallback mode (ignore gnome-shell)

I hated gnome-shell. I understand the distribution maintainers want to push new stuff into the audience, but I still feel most of the changes happened on Gnome 3 are pretty unfair for a desktop user. My computers are not a tablet, I can’t point with the finger, so this gnome-shell thing (Unity in Ubuntu, and alike) is just garbage for me. I don’t like them because they make me loose more time to find my things - which I had somehow inconsciently automated. So, obviously, I’m running in the “fallback mode“, which you can set using the gnome-control-center, on a unobvious “System Info” icon.

Delete key behaviour

After that, I spent some time trying to get back to the old behaviour, like using the DELETE key for what it used to do: delete stuff. Through the following command, you’ll be able to mouseover menu options and set the accelerator (shortcut) by pressing DELETE twice on the option “Move to Trash”. Learn more here.

gsettings set org.gnome.desktop.interface can-change-accels true

Desktop area management and icons

I believe this has been forgotten about the fallback mode: we used to have icons and be able to create folders and other nautilus operations, so I want that…. again. You can use dconf-editor to edit the configuration visually or using gsettings, again:

yum install dconf-editor
gsettings set org.gnome.desktop.background show-desktop-icons true

Adding menu entries

Maybe it’s just a fallback miss, but it won’t originally let you modify the Applications menu. For that, you’ll have to install alacarte and run it from console (or ALT+F2):

yum install alacarte

The entries created with alacarte (0.13.2-3) will miss the category no matter if you specify it on item creation. To place the icons where they’re due, you’ll have to edit the shortcuts, which are placed at ~/.local/share/applications. Just add an entry Categories=Development (example) and wait a couple of seconds so the panel freshens up. If you’re wondering about which categories to place, grep through /usr/share/applications/*.desktop for examples.


I was reading some of the powertop suggestions and doing some reading in the meanting, so these seemed to be worth considering:

Disable NMI Watchdog (ref):

echo 0 > /proc/sys/kernel/nmi_watchdog

Set wwan0 down if you’re not going to use it

ifconfig wwan0 down &

Disable Wake-up On LAN:

ethtool -s eth0 wol d &

Enable laptop mode, I don’t know if it’s still relevant nowadays (ref):

echo 5 > /proc/sys/vm/laptop_mode

Some interesting stuff I read on LessWatts:
Scheduler tunables for multi-socket systems (ref

echo 1 > /sys/devices/system/cpu/sched_mc_power_savings
echo 1 > /sys/devices/system/cpu/sched_smt_power_savings

Set vm writeback to 10 secs (lose 10 secs on crash):

echo 1500 > /proc/sys/vm/dirty_writeback_centisecs

Disable bluetooth entirey

hciconfig hci0 down

Disable wireless - if you’r not going to use it… maybe this could be integrated with the physical switch of the Vaio…

ifconfig wlan0 down
modprobe -r iwlagn

Enable Audio HD powersave

echo 10 > /sys/module/snd_hda_intel/parameters/power_save &

I will hardly make any kind of power consumption comparison between Windows and Linux - I won’t be in Windows that long :-) - but, anyway, it makes sense to not leak power on unused components.

That’s all for now.

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HP G62

October 4th, 2010 ntavares Posted in en_US, hardware, linux driver, ubuntu No Comments »

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Some weeks ago I bought this very cool notebook, HP G62. I was quite impressed by its features, when compared with its price. I decided to go for Ubuntu 10.04 (Lucid), as I did for the Aspire D250, and got surprised the sound didn’t work out of the box. Everything else did, as it’s quite usual with Ubuntu - thanks to everyone involved in it - and a quick search was kind of scary.

Obviously I looked in the wrong places, and the solution is pretty easy, which I only now had time to fix. This sound card is reported as Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 05) and its required modules have been moved to a separate package. To get support for it is just a matter of:

apt-get install linux-backports-modules-alsa-2.6.32-23-generic

In fact, I really love this laptop. The only thing I dislike, well, *hate* is the keyboard. Someone at HP Labs wasn’t very smart, since they added a left column of (unusefull) “multimedia” keys right next to the standard layout. So, while you’re not used to it (which happens a lot when you switch between multiple computers all the time), you keep launching the calculator, printer spooler or even the e-mail client, just to name a few. As a matter of fact, it seems HP made everything so well that they couldn’t sell perfection so cheap. It’s obvious the layout designer doesn’t use a keyboard at all :-)

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Acer Aspire One D250

January 29th, 2010 ntavares Posted in en_US, hardware, linux driver No Comments »

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I did it. I went to FNAC and bought it. I really did it :)

I just got this new Acer Aspire One (D250).

I’ve installed UNetbootin on my Fedora and downloaded an Ubuntu 9.10 image. After deploying the image to a 2GB USB stick, and booting the netbook, it just went on booting without any trouble at all. That’s what I like in Ubuntu, and that’s what I need for this laptop. After booting, just went through the installer and, after a couple of questions, all was ready: Wi-fi, Ethernet, Microphone, Webcam, everything worked out-of-the-box. Even the Wifi led is working, against all odds :)

I went through a shared installation to keep things simple. I still have to investigate this further, but awesome as well is the fact the Ubuntu installer respected both Android and Windows 7. Both are still bootable, the first being booted without option (I think it’s my fault when I was asked how I’d like it to boot), then GRUB, and from there I can go wherever: Ubuntu or Windows 7.

Windows 7, as usual, didn’t seem prepared to partition adjustments. After first boot it started a filecheck (still the good’old CHKDSK, just imagine :)… after rebooting again, it was ready to stay. Luck for it that handled it afterall, as its days of existence here are probably limited.

So, this page is needing an update. Pending testing is now the card reader and the webcam. After that, I should update the page.

In the meantime, between reboots, I just found my newest addiction (on the phone, so far) online as well: Tower Bloxx :)

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About cloud computing

September 2nd, 2009 ntavares Posted in en_US, linux driver, scaling No Comments »

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Last Sunday I commented about Pedro’s opinion about cloud computing and thought I could give my blog a reversed trackback :) Here it goes:

I think Pedro’s message is important. Cloud marketing and fuzzing seems to be targetted to business decision making personnel. However, no matter what they try to look like, that’s a technical decision and I really think that companies just following this marketing hype will eventually get caught on those small contract letters. As a technician, I agree with Pedro on the enterprise [not] moving its core to the cloud, and that the prices are [still] overrated.

However, for medium-to-large traffic platforms, such that they require a complex setup (meaning >4 machines) cloud can be a solution very similar to what could be called Hardware-as-a-Service. Unavoidabily, you have to move this kind of platforms outside the core, even if they are on a DMZ. More, you don’t usually want to mix corporate traffic with specific platforms (eg. a multinational’s CRM, the company’s website, etc.). In this context, cloud adds as much value as a regular hosting company would do, IMO. No more, no less.

Having said that, I still think it has lots of potential for intermediate companies (and again, this lives in technical scope) to provide HW solutions to costumers by clicking and adding “resources” to a [kind of] shop cart and then split them accordingly to their needs. That’s pretty much how Amazon seems to work – not some VPS/sliced hosting we are getting used to. Also, I see benefit for large hosting companies (now these could be those VPS/sliced ones :) ) because they can turn the income on periodic basis to match the periodic costs. From this intermediate’s perspective, one of the great features of this cloud thing is that they have setup quite heterogeneous provising systems, which a regular company can’t handle – that is to say you could setup a small/medium/full-blown pile of servers with a few clicks. Time also costs money.

Of course, this is all theoretical while the prices remain so high. It seemed even worst from my searches (although I confess I didn’t explore in depth): you will pay much more with cloud to have there available the same resources you can find on typical dedicated hosting servers – but it’s also true you rarely use them at 100%, so you may eventually get more cost/performance benefit in the near future (because when you buy or rent hardware it’s very difficult to recover the cost).

My conclusion is that the cloud is trying to attract customers on the hype, and that makes our technical advice more needed than ever: explain to the client how to plan, how to implement, and how to scale and where exactly the cloud fits in. To them, my recommendation is this: being on the cloud just because “it’s cool” or because it (seems) so simple you won’t need specialized IT staff, will eventually turn against you.

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MySQL DATETIME vs TIMESTAMP vs INT performance and benchmarking with InnoDB

July 6th, 2009 ntavares Posted in en_US, linux driver, mysql, performance, sugarcrm No Comments »

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Following my tests with DATETIME vs vs TIMESTAMP vs INT performance and benchmarking with MyISAM storage engine, I’ve wondered about the performance impact using InnoDB, which is usually more peaky with I/O. Read the rest of this entry »

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Linux on HP/Compaq Deskpro DC7700

April 10th, 2009 ntavares Posted in en_US, hardware, linux driver, performance No Comments »

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Although “Linux” seems a little vague, I’ve seen people complaining about their problems with this HP/Compaq model on almost any distribution. These small-form factor desktops are one of those labeled with Windows-ready logo - and support for in can only be found on HP’s forums. Actually, HP clearly states (somewhere) Linux is not supported. But… Read the rest of this entry »

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Monitorização de plataformas com cacti - LVS

April 4th, 2009 ntavares Posted in clustering, linux driver, monitorização, pt_PT 2 Comments »

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Descobri que existe um módulo completo de Net-SNMP para as estatísticas de IPVS, o net-snmp-lvs-module. O ponto de partida é, naturalmente, a FAQ de LVS, que nos leva para o dito cujo. Os gráficos talvez possam ser mais trabalhados, particularmente no que toca ao valor InActConn, mas para já não tenho tempo. Read the rest of this entry »

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Driver EPCAM para Linux

May 18th, 2008 ntavares Posted in epcam, linux driver, pt_PT No Comments »

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epcam thumbnailHá alguns dias atrás fui descobrir que havia pessoal a usar o driver EPCAM que eu, em 2004, tinha gerado a partir dos trabalhos de Jeroen Vreeken.

Sem lhe tirar o devido crédito, o driver deixou de funcionar praticamente após a transição 2.4->2.6 e, entretanto, envolvi-me noutras coisas, pelo que o driver ficou mais ou menos obsoleto (para o que ajudaram também as várias alterações ao Video4Linux, e sua versão 2). Por mero acidente, localizei o thread acima nos UbuntuForums e, finalmente este fim-de-semana, pude testar o driver e - surpresa das surpresas - trabalha melhor que nunca! Por isso, se por acaso tens uma Creative Webcam (PD1001), experimenta!

De pequena área na minha homepage, e agora que somos mais do que dois (eventualmente) a participar neste projecto, decidi registar o projecto na; estou à espera que o pessoal adira, e já recebi respostas positivas.

Lamento não poder ajudar mais, mas ainda bem que não foi tempo desperdiçado… esta é uma das coisas que me fascina no Open Source.

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