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Firmware Implementation Techniques to Achieve Windows® 8 Fast Boot

UEFI Summer Summit – July 16-20, 2012 Presented by Jeff Bobzin

Insyde Software

UEFI Summer Summit – July 2012 www.uefi.org 1

Updated 2011-06-01

Agenda

• Introduction and Goals

• Cost of Early USB Enumeration

• Firmware Menu Entry Solution

• What if a Keyboard is Needed?

• Other Elements

• Q & A

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Introduction and Goals

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What Were Our Goals?

• Faster Boot – better turn-on experience

• Streamline boot of installed OS from disk

• Allow other boot targets when needed

• Allow user access to firmware menus when needed

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Firmware/OS Cooperation

• Example of system improvement only possible due to cooperation facilitated by UEFI – Available to all firmware vendors

– Available to all OS vendors

– Available in Win 8 public Beta

– Full function in Insyde current versions

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Cost of Early USB Enumeration

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Impact of USB Enumeration on Firmware Boot Times

• When the Firmware enumerates the USB bus and searches for keyboard system time-to-boot is increased

• USB bus has certain architected delays

• If multiple devices are attached, the total delay increases

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0

0.5

1

1.5

2

2.5

3

3.5

4

0 USB K/M + Flash Dr. + hard drive

DT

NB

Firmware Portion of System Boot from Shutdown (SSD Disk)

Skipping USB Enumeration

• Skipping USB enumeration pays immediate benefits in faster boot

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0

0.5

1

1.5

2

2.5

3

3.5

4

0 USB K/M + Flash Dr. + hard drive

DT

NB

Firmware Boot Time when skipping USB Enumeration

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0

0.5

1

1.5

2

2.5

3

3.5

4

0 USB K/M + Flash Dr. + hard drive

w/USB

Skip USB

Improvement when Skipping USB Enumeration

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0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

0 USB K/M + Flash + Hard Dr.

DT

NB

Boot Time Penalty for Connected USB Devices

Firmware Menu Entry Solution

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How to Reach Firmware Menus?

• Skipping USB enumeration removes USB keyboard as tool for user interrupting boot to go to firmware menus

• NOTE – PS/2 style keyboard on NB embedded controller is still available

– But boot speed is so fast it may be hard for user to hit correct key quickly enough!

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New OsIndications Variables

• User can use OS menus to signal need for firmware menu

• OS signals to firmware via new variables

–Added UEFI Spec Update 2.3.1C

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New UEFI Variables for F/W <-> OS Signaling

New UEFI Variable

OsIndicationsSupported Allows the firmware to indicate supported features and actions to the OS.

OsIndications Allows the OS to request the firmware to enable certain features and to take certain actions.

Defined Indicator Bit

EFI_OS_INDICATIONS_BOOT_TO_FW_UI 0x0000000000000001

UEFI Summer Summit – July 2012 www.uefi.org 16

Windows® 8 Menu Navigation to Request Firmware On Reboot

Settings | Change PC Settings |

General | Advanced Startup [Restart] |

Troubleshoot | Advanced Options |

UEFI Firmware Settings |

[Restart]

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What if a Keyboard is Needed by OS Bootloader?

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Scenarios that Require Firmware Keyboard Initialization

1. Bootloader needs keyboard

2. Non-Standard Boot Target

3. Default Boot Fails

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Bootloader Requests Keyboard Wakeup

• Example Scenarios:

– Bitlocker Pin

– GRUB or other Bootloader Options

• When OS bootloader performs first EFI_SIMPLE_TEXT_INPUT_EX_PROTOCOL. ReadKeyStrokeEx() the deferred USB Enumeration is performed

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Win 8 Menu for Alt. Device Boot

• Windows® 8 provides BootNext select

Settings | Change PC Settings |

General | Advanced Startup [Restart] |

Troubleshoot |

Use A Device| [Boot-Device]

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Other Elements

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Automatic Enumeration

• USB is enumerated if primary boot target (BootNext or top of BootOrder) is not hard disk

– Example – USB boot is top of BootOrder list

• USB is enumerated if primary boot target fails to boot

– Facilitate recovery scenarios

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Opt-in or Opt-out

• Skipping USB Enumeration allows faster boot

– But will it confuse users?

• OEM has decision

– Should new behavior be Factory Default ?

Consider:

1. System Type

2. OS Vendor Recommendations

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Streamlined Boot Priority

• This technology is built on earlier improvements including:

– Skip media checks for removable media

–Pre-set OS boot variables are always top priority

• Streamlined procedure departs from Legacy BIOS tradition

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Questions and Answers

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Thanks for attending the UEFI Summer Summit 2012

For more information on the Unified EFI Forum and UEFI Specifications, visit http://www.uefi.org

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UEFI Summer Summit – July 2012 www.uefi.org 27