Attachment 248494 Details for Bug 272507 – 0001-acpi-Defer-reserving-resources-for-ACPI-devices.patch

[patch] 0001-acpi-Defer-reserving-resources-for-ACPI-devices.patch

0001-acpi-Defer-reserving-resources-for-ACPI-devices.patch (text/plain), 3.12 KB, created by John Baldwin on 2024-02-15 19:04:41 UTC

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Creator: John Baldwin

Created: 2024-02-15 19:04:41 UTC

Size: 3.12 KB

patch

obsolete

>From cb3a9259292f409ef577b142872a200d50bc5800 Mon Sep 17 00:00:00 2001
>From: John Baldwin <jhb@FreeBSD.org>
>Date: Thu, 15 Feb 2024 10:56:45 -0800
>Subject: [PATCH] acpi: Defer reserving resources for ACPI devices
>
>The goal of reserving firmware-assigned resources is to ensure that
>"wildcard" resource allocation requests will not claim an address
>range that is actually in use even if no attached driver is actively
>using that range.  However, the current approach can break in some
>cases.
>
>In particular, ACPI can enumerate devices behind PCI bridges that
>don't show up in a normal PCI scan, but those device_t objects can end
>up as direct children of acpi0.  Reserving resources for those devices
>directly from acpi0 ends up conflicting with later attempts to reserve
>the PCI bridge windows.
>
>As a workaround, defer reserving unclaimed resources until after the
>initial probe and attach scan.  Eventually this pass of reserving
>unclaimed resources can be moved earlier, but it requires changes to
>other drivers in the tree to permit enumerating devices and reserving
>firmware-assigned resources in a depth-first traversal before
>attaching devices whose drivers request wildcard allocations.
>
>PR:		272507
>---
> sys/dev/acpica/acpi.c | 22 +++++++++++++++++-----
> 1 file changed, 17 insertions(+), 5 deletions(-)
>
>diff --git a/sys/dev/acpica/acpi.c b/sys/dev/acpica/acpi.c
>index 43aed279ab35..defca923e36c 100644
>--- a/sys/dev/acpica/acpi.c
>+++ b/sys/dev/acpica/acpi.c
>@@ -1369,8 +1369,17 @@ acpi_sysres_alloc(device_t dev)
> }
> 
> /*
>- * Reserve declared resources for devices found during attach once system
>- * resources have been allocated.
>+ * Reserve declared resources for active devices found during the
>+ * namespace scan once the boot-time attach of devices has completed.
>+ *
>+ * Ideally reserving firmware-assigned resources would work in a
>+ * depth-first traversal of the device namespace, but this is
>+ * complicated.  In particular, not all resources are enumerated by
>+ * ACPI (e.g. PCI bridges and devices enumerate their resources via
>+ * other means).  Some systems also enumerate devices via ACPI behind
>+ * PCI bridges but without a matching a PCI device_t enumerated via
>+ * PCI bus scanning, the device_t's end up as direct children of
>+ * acpi0.  Doing this scan late is not ideal, but works for now.
>  */
> static void
> acpi_reserve_resources(device_t dev)
>@@ -2257,9 +2266,6 @@ acpi_probe_children(device_t bus)
>     /* Pre-allocate resources for our rman from any sysresource devices. */
>     acpi_sysres_alloc(bus);
> 
>-    /* Reserve resources already allocated to children. */
>-    acpi_reserve_resources(bus);
>-
>     /* Create any static children by calling device identify methods. */
>     ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "device identify routines\n"));
>     bus_generic_probe(bus);
>@@ -2268,6 +2274,12 @@ acpi_probe_children(device_t bus)
>     ACPI_DEBUG_PRINT((ACPI_DB_OBJECTS, "acpi bus_generic_attach\n"));
>     bus_generic_attach(bus);
> 
>+    /*
>+     * Reserve resources allocated to children but not yet allocated
>+     * by a driver.
>+     */
>+    acpi_reserve_resources(bus);
>+
>     /* Attach wake sysctls. */
>     acpi_wake_sysctl_walk(bus);
> 
>-- 
>2.42.0
>

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