Hi Sami, On Tue, 19 May 2026 at 16:40, Sami Mujawar <[email protected]> wrote: > I agree the behaviour is not immediately obvious when looking only at the PR. > I was initially confused as well when first reviewing the issue. > > The DynamicTablesManagerDxe installs an event notification for when both > gEfiAcpiTableProtocolGuid and gEfiSmbiosProtocolGuid become available, see > https://github.com/tianocore/edk2/blob/master/DynamicTablesPkg/Drivers/DynamicTableManagerDxe/DynamicTableManagerDxe.c#L61-L90 > > The EfiCreateProtocolNotifyEvent() invokes the event notification handler > function in the following situations > > if the protocol instance already exists > Whenever the protocol is installed/reinstalled > At least once even if the protocol is not installed. > > The documentation extract for the last case is as below > > > If there are no instances of ProtocolGuid in the handle database at the > time this function is invoked, > > then the notification function is still executed one time > > Please see > https://github.com/tianocore/edk2/blob/master/MdePkg/Library/UefiLib/UefiLib.c#L106-L108
Urgh. Thanks for the explanation. OK, I guess that means I reduce the strength of my objection. But I still question why it needs patching during hard freeze if it went unnoticed for seven months and two stable tags. I mean, it's annoying for whoever manages not to have the lines in their build config in an order that hid this problem, but surely a patch such as this would be easy to cherry-pick? > The check in the PR is handling the case 3 above. > > The DEPEX was removed as we want to support platforms that generate only ACPI > tables without requiring SMBIOS support. > The previous DEPEX effectively enforced both protocols as load-order > dependencies, which prevented this usage model. > > The current functionality should allow processing of ACPI tables or SMBIOS > tables whenever the protocol becomes available. > > Hope that clarifies the situation. It does, thanks. But this effectively also means that depending on module load order, this handler could end up being invoked several times if any other modules also register a notify event on the same protocol, including potentially after the protocol becomes available. Does the driver safely handle that? Best Regards, Leif -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#121962): https://edk2.groups.io/g/devel/message/121962 Mute This Topic: https://groups.io/mt/119390195/21656 Group Owner: [email protected] Unsubscribe: https://edk2.groups.io/g/devel/unsub [[email protected]] -=-=-=-=-=-=-=-=-=-=-=-
