Embedded Linux Power Management on the Intel Atom ... - MontaVista
Embedded Linux Power Management on the Intel Atom ... - MontaVista Embedded Linux Power Management on the Intel Atom ... - MontaVista
Modern POS systems • Many based on Intel Architecture and a variation of the standard “PC” platform. • Wide array of unusual on-board and off-board peripherals • Magstripe readers • PIN entry devices • Receipt printers • Touchscreens • Multiple displays • Cash drawers • Most commonly wall-socket powered with a local UPS for emergency operation. • Large retailers network POS devices. 4
- Page 1 and 2: Embedded L
- Page 3: Why care about Power</stron
- Page 7 and 8: How we save power Two big ways: •
- Page 9 and 10: ACPI / cpufreq Software Architectur
- Page 11 and 12: ACPI • ACPI is an open-industry s
- Page 13 and 14: What is Deep Power
- Page 15 and 16: L2 Dynamic Cache Sizing OS ACPI 8-W
- Page 17 and 18: Enumerate System Devices You'll nee
- Page 19 and 20: Identify Constraints Are there rela
- Page 22 and 23: Define Power <stro
- Page 24 and 25: Stitching it together • CPUfreq
- Page 26 and 27: The Governor • Task: Decide how a
- Page 28 and 29: ondemand Governor Example
- Page 30 and 31: Making Drivers Power</stron
- Page 32 and 33: cpufreq Notifications • Your driv
- Page 34 and 35: Saving power during idle • Idle S
- Page 36 and 37: Mitigate wakeups with Power
- Page 38 and 39: Free for the asking... “MontaVist
<str<strong>on</strong>g>Power</str<strong>on</strong>g> is a large factor in operati<strong>on</strong> costs<br />
• <str<strong>on</strong>g>Power</str<strong>on</strong>g> efficiency saves big m<strong>on</strong>ey<br />
• Drop power usage 33% <strong>on</strong> 5000 terminals: Save $1 milli<strong>on</strong> in<br />
7 years.<br />
• <str<strong>on</strong>g>Power</str<strong>on</strong>g> efficiency is <strong>on</strong> <strong>the</strong> mind of POS system<br />
purchasers<br />
• Retailers c<strong>on</strong>sider energy efficiency as a factor when selecting<br />
POS systems:<br />
Big Box: over 70%<br />
Grocery: over 50%<br />
Small Box: over 50%<br />
• As retail hours stretch...<br />
• Basic <strong>on</strong>/off power saving is limited.<br />
• Only 50% of big box retailers use <strong>on</strong>/off.<br />
• Saving power while open for business is essential.<br />
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