Hi Igor, On Tue, Jul 13, 2021 at 10:59 AM Igor Mammedov <imamm...@redhat.com> wrote:
> On Tue, 13 Jul 2021 02:42:04 +0200 > Julia Suvorova <jus...@redhat.com> wrote: > > > Q35 has three different types of PCI devices hot-plug: PCIe Native, > > SHPC Native and ACPI hot-plug. This patch changes the default choice > > for cold-plugged bridges from PCIe Native to ACPI Hot-plug with > > ability to use SHPC and PCIe Native for hot-plugged bridges. > > Before we flip the switch, > has the issue about not hotplug ports not getting IO (Michael) > been addressed, if not are there any plans to fix it? > > Following an offline discussion with Michael the understanding is PCIe devices should work correctly without IO, so it only affects PCI devices hot-plugged into PCIe ports, but those devices should be plugged into pcie-pci bridges. Another alternative is to drop this patch and let ACPI hotplug be an option and not the default until we find a solution, meaning delaying the flip until 6.2 since today is the soft-freeze. I will let Michael decide, I am fine one way or the other. Thanks, Marcel > > > This is a list of the PCIe Native hot-plug issues that led to this > > change: > > * no racy behavior during boot (see 110c477c2ed) > > * no delay during deleting - after the actual power off software > > must wait at least 1 second before indicating about it. This case > > is quite important for users, it even has its own bug: > > https://bugzilla.redhat.com/show_bug.cgi?id=1594168 > > * no timer-based behavior - in addition to the previous example, > > the attention button has a 5-second waiting period, during which > > the operation can be canceled with a second press. While this > > looks fine for manual button control, automation will result in > > the need to queue or drop events, and the software receiving > > events in all sort of unspecified combinations of attention/power > > indicator states, which is racy and uppredictable. > > * fixes: > > * https://bugzilla.redhat.com/show_bug.cgi?id=1752465 > > * https://bugzilla.redhat.com/show_bug.cgi?id=1690256 > > > > To return to PCIe Native hot-plug: > > -global ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off > > > > Signed-off-by: Julia Suvorova <jus...@redhat.com> > > Reviewed-by: Igor Mammedov <imamm...@redhat.com> > > --- > > hw/acpi/ich9.c | 2 +- > > hw/i386/pc.c | 1 + > > 2 files changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c > > index 2f4eb453ac..778e27b659 100644 > > --- a/hw/acpi/ich9.c > > +++ b/hw/acpi/ich9.c > > @@ -427,7 +427,7 @@ void ich9_pm_add_properties(Object *obj, > ICH9LPCPMRegs *pm) > > pm->disable_s3 = 0; > > pm->disable_s4 = 0; > > pm->s4_val = 2; > > - pm->use_acpi_hotplug_bridge = false; > > + pm->use_acpi_hotplug_bridge = true; > > > > object_property_add_uint32_ptr(obj, ACPI_PM_PROP_PM_IO_BASE, > > &pm->pm_io_base, OBJ_PROP_FLAG_READ); > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > > index 8e1220db72..7e03848792 100644 > > --- a/hw/i386/pc.c > > +++ b/hw/i386/pc.c > > @@ -98,6 +98,7 @@ GlobalProperty pc_compat_6_0[] = { > > { "qemu64" "-" TYPE_X86_CPU, "family", "6" }, > > { "qemu64" "-" TYPE_X86_CPU, "model", "6" }, > > { "qemu64" "-" TYPE_X86_CPU, "stepping", "3" }, > > + { "ICH9-LPC", "acpi-pci-hotplug-with-bridge-support", "off" }, > > }; > > const size_t pc_compat_6_0_len = G_N_ELEMENTS(pc_compat_6_0); > > > >