lca2013 – Day 3 – Session 1

So after a late night hustling people at foosball and swapping rumours about a certain person being ejected from the conference, I managed to leave my key in my room in the rush to get to the opening (although in the end I caught a bus).

The winner of The Rusty Wrench award was Donna Benjamin this year, I liked the way she talked about each of the past winners and got everybody to acknowledge them ( Rusty, Pia, Mary and Kim ).

 Think, Create & Critique Design by Andy Fitzsimon

” I’m a drinker with a speaking problem ”

We are all designers

Fundamentals of design

  • Elements and principals of design
  • Like cooking – ingredients create flavours influencing a meal
  • Elements are the raw tools:
    • Line – continious path between two points, process, plot
    • Shape – When I line joins around to cover an area – shapes used to explan something (pymrid scheme )
    • Space – positive and negative
    • Size
    • Colour
    • Value
    • Texture – structure and feel
  • Principles
    • made with elements and with other priciples
    • proportion
    • Pattern – using same element multiple times
    • Graduation – incremental changes to one element over another
    • Balance / Harmony / Unity – One or more elements creating a cohesion
    • Contrast – abrupt difference between elements creating a compostion
    • Emphasis
    • Form – The “whole” that the sum of the parts make
    • Gestalt


  • Visual Design
  • The Swiss Won – “International Typographic Style”
    • Typographic
    • Famously minimalistic
    • easy to critique and easier to impliment
    • Baseline grid – can check with a ruler
    • Always follows a vertical rhythm
    • If you have a design you already have a grid
    • A varied scale – Robert Bringhurst
  • Art Nouveau
    • Hard to do
  • Style tiles and brand guides


  • Patterns
  • Wireframe
  • Workflow
  • Persona
  • Analytics
  • Instrumentation
  • Surveys
  • Reviews
  • User Testing

Have some common sense

Interactive design

  • Progressive disclosure
  • Form follows function
  • Affordance
  • Hyper realism vs skeumorphism
    • Hyper realism – makes things look real
    • skeu – reminds you of something real

Experience design

  • Deliberate differences
  • think, make, become (take ownership, win with empathy!)

Nail the hierarchy of needs

  • Lovable
  • meaningful
  • pleasurable
  • convienient
  • predictable
  • purposeful
  • They are easy to observe but hard to tell
  • damned hard to hit them all

Good design is a process

  • Design thinking
    • It is a quick workflow
    • define
    • find
    • guess
    • try
    • check
    • do
    • learn

Failing at life is helps you design

Design for hacker is a great book, if you can stomach apple worship and web 2.0

Bunch of other books..


Vampire Mice: How USB PM impacts you by Sarah Sharp

How USB power Management works

  • 3 types of management
    • Device suspend
    • Host suspend
    • Link power management
  • Devices suspended when inactive
  • When all device on host you can suspend host
  • 1 device keeps host awake which keeps CPU awake
  • Device must to support suspend (according to spec)
    • But lots don’t
    • Drivers sometimes don’t
    • No USB transfers when suspended, so if userspace polling then can’t suspend

How USB power Mngt does not work

  • Drivers missing auto-suspend support
  • Impossible to get device to idle
  • Userspace polls device
    • Has a SD card been inserted yet?
  • USB suspend issues
    • Disconnect on resume
    • Unsafe suspend behaviour ( usb hard drive cut power to spinning disk without parking )
    • No remote wakeups ( mouse only wakes up when button pushed, not just when it is moved )
    • Event loss during resume
    • too risky to enable by default
  • Hard to tell if firmware version is good or bad
  • All sorts of weird issues with different platforms ( USB Hubs etc )

USB Device Suspend Issues

  • Blacklist to big to keep in the kernel
  • USB Device suspend off by default
  • Can be turn on by user (per device) via powertop
  • Powertop setting won’t persist across device unplugs or reboots
    • Solution: Create a udev rule


  • Try using powertop
  • Create Udev rule to keep

Challenges with USB device suspend

  • Users must turn on
  • Require driver modification
  • Timeout too course grained
  • Devices can’t refuse to allow suspend

USB 3.0 Link Power Management

  • Link Power Management states U1 and U2
  • Hosts and hubs track idleness
  • OS sets timeout once
  • No driver modification
  • Devices can refuse U1 and U2
  • Some vendors don’t like Link PM – can be detected
  • Some Hubs don’t support either
  • USB 2.1
    • New L1 state
    • No changes to USB 2.0 hubs

New Intel stuff

  • Panther Point vs Lynx Point chipsets
  • Panther Point
    • Has xHCI controller
    • Only 4 points under xHCI
    • Supports USB 3.0 Link PM
  • Lynx Point
    • All Ports
    • Supports 3.0 PM and 2.1 PM
    • Completely unused ports can be turned off completely


Actual saving is Probably more than you think, especially if you get the whole chain to sleep.

Somebody said “about 4 watts” for SandyBridge

Servers can also save. Options in HP G7 servers. But problems