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Re: [RFC PATCH] hw/acpi: do not let OSPM set pcie native hotplug when ac
From: |
Michael S. Tsirkin |
Subject: |
Re: [RFC PATCH] hw/acpi: do not let OSPM set pcie native hotplug when acpi hotplug is enabled |
Date: |
Mon, 5 Sep 2022 06:53:56 -0400 |
On Mon, Sep 05, 2022 at 12:55:31PM +0530, Ani Sinha wrote:
> Possible fix for https://bugzilla.redhat.com/show_bug.cgi?id=2089545
>
> Change in AML:
>
> @@ -47,33 +47,39 @@
> Scope (_SB)
> {
> Device (PCI0)
> {
> Name (_HID, EisaId ("PNP0A08") /* PCI Express Bus */) // _HID:
> Hardware ID
> Name (_CID, EisaId ("PNP0A03") /* PCI Bus */) // _CID:
> Compatible ID
> Name (_ADR, Zero) // _ADR: Address
> Name (_UID, Zero) // _UID: Unique ID
> Method (_OSC, 4, NotSerialized) // _OSC: Operating System
> Capabilities
> {
> CreateDWordField (Arg3, Zero, CDW1)
> If ((Arg0 == ToUUID ("33db4d5b-1ff7-401c-9657-7441c03dd766")
> /* PCI Host Bridge Device */))
> {
> CreateDWordField (Arg3, 0x04, CDW2)
> CreateDWordField (Arg3, 0x08, CDW3)
> Local0 = CDW3 /* \_SB_.PCI0._OSC.CDW3 */
> - Local0 &= 0x1E
> + Local0 &= 0x1F
> + Local1 = (CDW3 & One)
> + If ((One == Local1))
> + {
> + CDW1 |= 0x12
> + }
> +
> If ((Arg1 != One))
> {
> CDW1 |= 0x08
> }
>
> If ((CDW3 != Local0))
> {
> CDW1 |= 0x10
> }
>
> CDW3 = Local0
> }
> Else
> {
> CDW1 |= 0x04
> }
> **
>
> Signed-off-by: Ani Sinha <ani@anisinha.ca>
> ---
> hw/i386/acpi-build.c | 23 ++++++++++++++++++++---
> 1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 0355bd3dda..3dc9379f27 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1348,10 +1348,12 @@ static Aml *build_q35_osc_method(bool
> enable_native_pcie_hotplug)
> {
> Aml *if_ctx;
> Aml *if_ctx2;
> + Aml *if_ctx3;
> Aml *else_ctx;
> Aml *method;
> Aml *a_cwd1 = aml_name("CDW1");
> Aml *a_ctrl = aml_local(0);
> + Aml *a_pcie_nhp_ctl = aml_local(1);
>
> method = aml_method("_OSC", 4, AML_NOTSERIALIZED);
> aml_append(method, aml_create_dword_field(aml_arg(3), aml_int(0),
> "CDW1"));
> @@ -1366,11 +1368,26 @@ static Aml *build_q35_osc_method(bool
> enable_native_pcie_hotplug)
> /*
> * Always allow native PME, AER (no dependencies)
> * Allow SHPC (PCI bridges can have SHPC controller)
> - * Disable PCIe Native Hot-plug if ACPI PCI Hot-plug is enabled.
> */
> - aml_append(if_ctx, aml_and(a_ctrl,
> - aml_int(0x1E | (enable_native_pcie_hotplug ? 0x1 : 0x0)), a_ctrl));
> + aml_append(if_ctx, aml_and(a_ctrl, aml_int(0x1F), a_ctrl));
>
> + /*
> + * if ACPI PCI Hot-plug is enabled, do not let OSPM set OSC PCIE
> + * Native hotplug ctrl bit.
> + */
> + if (!enable_native_pcie_hotplug) {
> + /* check if the ACPI native hotplug bit is set by the OS in DWORD3 */
> + aml_append(if_ctx, aml_and(aml_name("CDW3"),
> + aml_int(0x01), a_pcie_nhp_ctl));
> + if_ctx3 = aml_if(aml_equal(aml_int(1), a_pcie_nhp_ctl));
> + /*
> + * ACPI spec 5.1, section 6.2.11
> + * bit 1 in first DWORD - _OSC failure
> + * bit 4 in first DWORD - capabilities masked
> + */
> + aml_append(if_ctx3, aml_or(a_cwd1, aml_int(0x12), a_cwd1));
0x12 ->
( 0x1 << 4 ) /* _OSC failure */ | ( 0x1 << 1) /* capabilities masked */
> + aml_append(if_ctx, if_ctx3);
> + }
> if_ctx2 = aml_if(aml_lnot(aml_equal(aml_arg(1), aml_int(1))));
> /* Unknown revision */
> aml_append(if_ctx2, aml_or(a_cwd1, aml_int(0x08), a_cwd1));
Hmm wait a sec
if_ctx2 = aml_if(aml_lnot(aml_equal(aml_name("CDW3"), a_ctrl)));
/* Capabilities bits were masked */
aml_append(if_ctx2, aml_or(a_cwd1, aml_int(0x10), a_cwd1));
aml_append(if_ctx, if_ctx2);
this one seems subtly different ...
> --
> 2.34.1