Enabling battery conservation mode no longer works on Linux 5.12.x for Lenovo Legion 5 15ARH05.
It works with kernel versions 5.11 and 5.10 on Arch Linux.
Modifying `/sys/bus/platform/drivers/ideapad_acpi/VPC2004:00/conservation_mode` fails with message : `Input/output error`
Thanks for bringing this up. The issue has already been reported in https://bugzilla.kernel.org/show_bug.cgi?id=212985 and a patch has been sent to fix it ( https://email@example.com/ ).
I've added the patch fixing this to the fixes branch of the pdx86 kernel tree:
The contents of this branch will be in the next pdx86-fixes pull-req which I send to Linus for 5.13. Since the patch has a fixes tag it will get added automatically to the 5.12 kernels once Linus has merged it, so this bug can be closed now.