https://bugzilla.kernel.org/show_bug.cgi?id=219044
xiaojian...@amd.com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |xiaojian...@amd.com
--- Comment #2 from xiaojian...@amd.com ---
(In reply to Nicolas Granger from comment #0)
> acpi_cppc seems to fail to detect _CPC support on Lenovo Yoga Pro 7 14AHP9.
> This causes linux to fall back to acpi pstate by default or to discard epp
> support if amd_pstate=active is passed on the cmdline.
>
> When booting with "amd_pstate=active amd_pstate.dyndbg=+p
> cppc_acpi.dyndbg=+p debug" on the command line, dmesg[1] contains the
> following lines about CPC:
>
> [ 0.437698] ACPI CPPC: Parsed CPC struct for CPU: 0
> ...
> [ 0.502121] ACPI CPPC: _CPC in PCC is not supported
>
> On windows, the hwinfo tool mentions CPPC support (the interface is
> confusing, I can launch it again with guidance on what to look for). It also
> reports the CPU core frequencies go as low as 1GHz with a high percentage in
> C6 state. On linux, acpi pstate can only reach 1.6GHz minimum, with
> amd_pstate=active, `cpupower monitor` reports frequencies above 2GHz.
>
> In the ACPI tables[2], _CPC entries are present[3].
>
> The bios changelog[4] mentions "1.Follow AMD's suggest, Disabling DVFS
> temporarily to mitigate the BSOD on UUT with Micron memory." which is
> unclear to me.
>
This change is related to memory, not cpu freq.
>
> System information:
>
> - Laptop model: Lenovo Yoga Pro 7 14AHP9
> - BIOS version: 1.16 (NCCN16WW 02/02/2024)
> - Processor: AMD Ryzen 7 8845HS
> - Kernel: 6.9.8 (Arch linux)
>
> [1]
> https://gist.github.com/nlgranger/9eae8ea594930e605f22d1ae6ecbf49f#file-dmesg
> [2]
> https://gist.github.com/nlgranger/9eae8ea594930e605f22d1ae6ecbf49f#file-
> acpidump
> [3]
> https://gist.github.com/nlgranger/9eae8ea594930e605f22d1ae6ecbf49f#file-
> ssdt11-dsl-L380
> [4] https://download.lenovo.com/consumer/mobiles/nccn16ww.txt
--
You may reply to this email to add a comment.
You are receiving this mail because:
You are watching the assignee of the bug.
_______________________________________________
acpi-bugzilla mailing list
acpi-bugzilla@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla
