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Support for Real-Time Clock via SAM #9
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Some notes:
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There is indeed a More open questions:
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Clarification on this: The respective SAM request still works (provided one gives the index to the timer as payload, i.e. 0 or 1 as u32, see ACPI spec). So do we actually need to access system memory or can we rely on SAM here? |
Very basic RTC support has been implemented in linux-surface/kernel@6b289bf. This does not support any kind of alarms yet. For testing wake alarms/interrupts properly, we may need to make suspend work first. |
Discussion on the built-in Qualcomm RTC and why that doesn't allow setting time: https://discuss.96boards.org/t/how-to-enable-rtc-on-dragonboard-410c-with-linaro-15-07/188/19. |
The RTC used by Qualcomm uses an offset stored as UEFI variable for correction ( A series to better support this RTC is being upstreamed: https://lore.kernel.org/lkml/20230202155448.6715-1-johan+linaro@kernel.org/ for details. |
The Surface Pro X exposes a standard real-time clock ACPI interface (
ACPI000E
). This calls to the Surface Aggregator EC via the SAN interface. Add direct support for the RCT as SAM client device/driver combo. While not directly apparent in ACPI, there also seems to be a dedicated wake interrupt GPIO pin associated with the RTC.The text was updated successfully, but these errors were encountered: