On Fri, Jun 14, 2024 at 10:25 AM Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> wrote: > > > > 在2024年6月14日六月 上午3:11，Huacai Chen写道： > > Hi, Jiaxun, > > > > On Fri, Jun 14, 2024 at 12:41 AM Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx> wrote: > >> > >> Most LoongArch 64 machines are using custom "SADR" ACPI extension > >> to perform ACPI S3 sleep. However the standard ACPI way to perform > >> sleep is to write a value to ACPI PM1/SLEEP_CTL register, and this > >> is never supported properly in kernel. > > Maybe our hardware is insane so we need "SADR", if so, this patch may > > break real hardware. What's your opinion, Jianmin? > > I understand why your hardware need SADR. Most systems DDR self-refresh > mode needs to be setup by firmware. _S3 is also a firmware method, why we can't use it to setup self-refresh? Huacai > > There is no chance that it may break real hardware. When firmware supplied > SADR it will always use SADR. The fallback only happens when _S3 method exist > but no SADR supplied, which won't happen on real hardware. > > For QEMU we don't have stub firmware but standard compliant SEEP_CTL is > sufficient for entering sleep mode, thus we need this fallback path. > > Thanks > > > > > Huacai > > > >> > > -- > - Jiaxun >
