電子辞書で学ぶ Linux のサスペンド

情報科学若手の会 春の陣 2023 #wakate2023s

Transcript

1. 2023 #wakate
   2023
   s
   Linux
   aka @puhitaku
   

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2. 2
   Takumi Sueda @puhitaku
   
   
   
   
   
   
   HOMMA Inc.
   
   
   
   
   
   OSS etc.
   
   
   
   
   
   
   
   
   3
   D
   
   
   
   
   
   
   
   2014
   

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3. Linux Linux 3 5
   3
   

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4. SHARP Brain
   SHARP Brain
   4
   

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5. SHARP Brain
   SHARP Brain PW-SH
   1
   
   
   SHARP 2008
   
   
   Windows CE 2020
   
   
   CE
   
   
   exe
   
   
   Brain 2ch
   
   
   Brain Windows CE
   
   
   
   
   Wikipedia
   
   
   matplotlib
   
   
   

   5
   

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6. SHARP Brain 6
   DRAM: LPDDR
   128
   MB
   eMMC:
   8
   GB
   
   
   SD
   Raspberry Pi
   
   
   LCD
   CPU: NXP i.MX
   2
   83
   
   ARM
   926
   EJ-S, armv
   5
   tej
   
   
   4
   54
   MHz
   LCD:
   8
   00
   x
   48 0
   SD: SDXC
   
   
   :
   
   
   
   

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7. SHARP Brain
   SHARP Brain PW-SH
   1
   U-Boot Linux
   
   
   2020 Brain U-Boot
   

   Linux
   
   
   Raspberry Pi SD
   

   Linux
   
   
   
   LCD
   
   
   
   
   
   SD / eMMC
   
   

   etc ...
   7
   

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8. SHARP Brain
   SHARP Brain PW-SH
   1
   
   
   
   
   
   cpufreq CPU
   
   
   8
   🤔
   

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9. SHARP Brain
   SHARP Brain PW-SH
   1
   
   
   
   
   
   cpufreq CPU
   
   
   9
   🤔
   

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11. Suspend-to-Idle
    
    
    Standby
    
    
    Suspend-to-RAM
    
    
    Hibernation
    
    
    Linux
    11
    "sleep", "system-wide sleep"
    

    

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12. 1
    . Suspend-to-Idle
    2
    . Standby
    😴 Userspace
    
    
    😴 Timekeeping tick,
    
    
    😴 I/O
    CPU
    
    
    CPU
    
    
    😴 Suspend-to-Idle
    
    
    😴 Non-boot CPU
    3
    . Suspend-to-RAM
    😴 Standby
    
    
    😴
    CPU DRAM
    
    
    DRAM
    4
    . Hibernation
    😴
    CPU
    
    
    

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13. 1
    . Suspend-to-Idle
    2
    . Standby
    😴 Userspace
    
    
    😴 Timekeeping
    
    
    😴 I/O
    CPU
    
    
    CPU
    
    
    😴 Suspend-to-Idle
    
    
    😴 Non-boot CPU
    3
    . Suspend-to-RAM
    😴 Standby
    
    
    😴
    CPU DRAM
    
    
    DRAM
    4
    . Hibernation
    😴
    CPU
    
    

    

    Suspend-to-RAM
    

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14. Suspend-to-RAM
    

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15. Suspend-to-RAM
    1
    .
    
    
    2
    .
    
    
    3
    . &
    
    
    4
    . Non-boot CPU CPU IRQ Boot CPU
    
    
    5
    . tick
    
    
    6
    . RAM
    
    
    7
    .
    Suspend-to-RAM
    15
    

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16. Suspend-to-RAM
    1
    .
    
    
    2
    . CPU
    
    
    
    
    3
    .
    
    
    4
    . tick
    
    
    5
    . Non-boot CPU
    
    
    6
    . IRQ
    
    
    7
    . (thaw = )
    
    
    8
    .
    Suspend-to-RAM
    16
    

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17. Suspend-to-RAM
    
    
    

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18. Suspend-to-RAM
    Suspend-to-RAM 2
    18
    Brain
    
    
    SoC
    
    
    MOSFET
    GPIO
    
    
    SPI, I²C
    graceful
    
    
    dev_pm_ops
    
    
    
    
    
    Device Tree
    Power Management Subsystem
    

    ISR
    
    
    Brain
    
    
    
    GPIO
    

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19. Suspend-to-RAM
    /sys/power/state write
    
    
    19
    i.MX
    28
    Device Tree
    
    
    LCD
    
    
    Suspend-to-RAM Device Tree
    

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20. Suspend-to-RAM 20
    
    
    Suspend-to-RAM
    1.
    
    
    pm_wakeup_event
    
    
    PM subsystem
    
    
    2
    . suspend_enter CPU PC
    
    
    
    
    
    CPU
    
    
    /drivers/input/keyboard/gpio_keys.c L
    44 3
    (Linux
    5
    .
    4
    .
    2 3
    4
    )
    /kernel/power/suspend.c L
    5 02
    (Linux
    5
    .
    4
    .
    2 34
    )
    

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21. Brain
    

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22. Brain
    ✅ Suspend-to-RAM
    
    
    ✅ GPIO
    
    
    ⬜ MCU I²C
    
    
    I²C
    
    
    ISR
    
    
    Windows
    
    
    ⬜ LCD
    
    
    FET ENABLE GPIO regulator Device Tree
    
    
    ⬜
    
    
    ⬜ OS
    Suspend-to-RAM
    22
    

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23. suspend_prepare suspend_freeze_processes [1] userspace
    
    
    [
    1
    ] https://elixir.bootlin.com/linux/v
    5
    .
    4
    .
    23
    4
    /source/kernel/power/power.h#L
    250
    Q. kthread userspace
    23
    Q.
    4
    SoC
    Suspend-to-Idle Brain SoC
    115mA
    86
    mA [1] Brain Standby
    Suspend-to-Idle Suspend-to-RAM LCD
    
    
    [
    1
    ] https://twitter.com/puhitaku/status/
    1
    62
    984
    98
    629
    24
    6484
    55
    

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24. Bootlin Elixir: https://elixir.bootlin.com/linux/v
    5
    .
    4
    .
    2
    34
    /
    
    
    Mainline Linux
    
    
    /Documentation/admin-guide/pm/suspend-
    fl
    ows.rst
    
    
    /Documentation/admin-guide/pm/sleep-states.rst
    24
    

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