Public bug reported:
[Impact]
Some GB10 firmware configurations do not expose the RTC EFI service. On
these systems, the ACPI Time and Alarm Device (ACPI000E) is the only
available real-time clock.
The current linux-nvidia kernel does not expose this device through the
Linux RTC class. Consequently, standard userspace RTC interfaces are not
available when rtc-efi is absent.
[Fix]
Backport the upstream ACPI TAD RTC-class support and the associated x86
CMOS RTC platform-device reorganization from Linux v7.1.
The backport preserves the existing ACPI_HANDLE() NULL check carried by
the 26.04 kernel while removing the obsolete address-space-handler setup.
Include the applicable upstream follow-up fixes:
- 77dd14ab1b57 ("ACPI: TAD: Use devres for all driver cleanup")
Prevents RTC callbacks from racing with TAD driver teardown.
- e9f850ba66cd ("rtc: cmos: Use platform_get_irq_optional() in
cmos_platform_probe()")
Preserves the legacy CMOS RTC IRQ fallback and alarm functionality.
- f706a63fd822 ("ACPI: TAD: Use DC wakeup only if AC wakeup is supported")
Rejects invalid DC-only wake capability combinations.
- 8522d806d84e ("ACPI: TAD: Check AC wake capability before enabling
wakeup")
Prevents RTC-only TAD devices from being incorrectly advertised as
wake-capable.
[Where problems could occur]
The changes affect ACPI TAD probing, RTC-class registration, wake
capability handling, runtime-PM teardown, and x86 CMOS RTC enumeration.
Incorrect capability handling could advertise unsupported wakeup
functionality. Incorrect cleanup ordering could race with RTC callbacks.
Incorrect CMOS IRQ handling could disable RTC alarm functionality on
some x86 systems. The listed upstream fixes address these known issues.
** Affects: linux-nvidia-bos (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2167888
Title:
[linux-nvidia]: ACPI: TAD: expose an RTC class device on GB10 systems
without RTC EFI
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