On Wed, May 05, 2021 at 01:13:57PM -0600, Alex Williamson wrote: > On Wed, 5 May 2021 23:10:32 +0530 > Amey Narkhede <ameynarkhede03@xxxxxxxxx> wrote: > > On 21/05/05 01:56PM, Oliver O'Halloran wrote: > > > On Wed, May 5, 2021 at 12:50 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > > > On Mon, May 03, 2021 at 09:07:11PM -0500, Shanker R Donthineni wrote: > > > > > On 5/3/21 5:42 PM, Bjorn Helgaas wrote: > > > > > > Obviously _RST only works for built-in devices, since there's no AML > > > > > > for plug-in devices, right? So if there's a plug-in card with this > > > > > > GPU, neither SBR nor _RST will work? > > > > > These are not plug-in PCIe GPU cards, will exist on upcoming server > > > > > baseboards. ACPI-reset should wok for plug-in devices as well as long > > > > > as firmware has _RST method defined in ACPI-device associated with > > > > > the PCIe hot-plug slot. > > > > > > > > Maybe I'm missing something, but I don't see how _RST can work for > > > > plug-in devices. _RST is part of the system firmware, and that > > > > firmware knows nothing about what will be plugged into the slot. So > > > > if system firmware supplies _RST that knows how to reset the Nvidia > > > > GPU, it's not going to do the right thing if you plug in an NVMe > > > > device instead. > > > > > > > > Can you elaborate on how _RST would work for plug-in devices? > > I'm not sure I really understand these concerns about plug-in devices. I'm not really concerned about plug-in devices. Shanker said above that _RST would work for them: ACPI-reset should work for plug-in devices as well as long as firmware has _RST method defined in ACPI-device associated with the PCIe hot-plug slot. and I disagreed. _RST *cannot* work for plug-in devices because firmware doesn't know what device will be plugged in and therefore cannot provide the required device-specific _RST. That's all I wanted to clarify. Bjorn
