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I uncovered an ACPI bug in my Dell Inspiron 5567. It was plaguing me for 8 years

10 hours ago
https://triangulatedexistence.mataroa.blog/blog/i-uncovered-an-acpi-bug-in-my-dell-inspiron-5667-it-was-plaguing-me-for-8-years/
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  • #ACPI
  • #FirmwareBug
  • #PowerManagement
  • A Dell Inspiron 5567 laptop has a persistent bug where closing the lid to put it to sleep sometimes causes it to reboot instead, occurring across multiple operating systems.
  • The issue was traced to a flaw in the firmware's ACPI (Advanced Configuration and Power Interface) tables, specifically in the _PTS (Prepare To Sleep) method.
  • The buggy code in the Southbridge's SPTS method incorrectly sets the sleep enable bit (SLPE) before properly configuring the sleep state, leading to unpredictable behavior.
  • The problem is exacerbated because the conditional logic for S3 sleep (suspend) is executed after the sleep enable command, making it ineffective.
  • The TPM (Trusted Platform Module) method (TPTS) correctly handles S4 (hibernate) and S5 (shutdown) states, but S3 sleep remains broken due to the Southbridge's flawed implementation.
  • The author emphasizes the need for better technical reviews of ACPI tables to ensure system stability, highlighting the frustration of dealing with such deep-seated firmware issues.
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