> -----Original Message----- > From: Ian Campbell > Sent: 09 May 2014 17:12 > To: Konrad Rzeszutek Wilk > Cc: Ross Philipson; ke...@koconnor.net; Huangweidong (C); Hanweidong > (Randy); m...@redhat.com; qemu-devel@nongnu.org; xen- > de...@lists.xen.org; fabio.fant...@m2r.biz; > johannes.kra...@googlemail.com; Gonglei (Arei); Stefano Stabellini; > Gaowei (UVP); Jan Beulich; Anthony Perard; Paul Durrant > Subject: Re: [Xen-devel] [PATCH v4] Hvmloader: Modify ACPI to only supply > _EJ0 methods for PCIslots that support hotplug by runtime patching > > On Fri, 2014-05-09 at 12:00 -0400, Konrad Rzeszutek Wilk wrote: > > > So we could just then gat the _EJ0 functionality based on values that > > are present (or not) in the SSDT ? > > AIUI the very presence of _EJ0 is what marks the device as being > ejectable (e.g. in the Windows device manager). > > It would be possible to make _EJ0 conditionally turn itself into a NOP > without resorting to an SSDT, but I don't think that solves the issue > they are trying to solve, which is that the user can even try to eject > an non-hotplug device. (grep for UAR1 in our dsdt.asl and > acpi_info->com1_present in hvmloader/acpi/build.c for an example of this > sort of conditional thing) >
Yes, ejectable is only part of it. If there's appropriate AML for the slot, it is enough to indicate that a device is removable. I found the following link to an old M$ doc describing hotplug PCI: http://www.microsoft.com/china/whdc/system/pnppwr/hotadd/hotplugpci.mspx. (There's a load of Chinese characters surrounding the doc, but the body is in English). Paul
