PCI / Hotplug: Always allow acpiphp to handle non-PCIe bridges

PATCH Applied Rafael J. Wysocki 2 participants 4 messages Dec 12, 2011 – Dec 13, 2011

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ACPI PCI

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Rafael J. Wysocki

author

2011-12-12 22:59 UTC #0 lore raw

PATCH 1/1 PCI / Hotplug: Always allow acpiphp to handle non-PCIe bridges

From: Rafael J. Wysocki <[email protected]>

Commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a (PCI / ACPI: Make acpiphp ignore root bridges using PCIe native hotplug) added code that made the acpiphp driver completely ignore PCIe root complexes for which the kernel had been granted control of the native PCIe hotplug feature by the BIOS through _OSC. Unfortunately, however, this was a mistake, because on some systems there were PCI bridges supporting PCI (non-PCIe) hotplug under such root complexes and those bridges should have been handled by acpiphp.

For this reason, revert the changes made by the commit mentioned above and make register_slot() in drivers/pci/hotplug/acpiphp_glue.c avoid registering hotplug slots for PCIe ports that belong to root complexes with native PCIe hotplug enabled (which means that the BIOS has granted the kernel control of this feature for the given root complex). This is reported to address the original issue fixed by commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a and to work on the system where that commit broke things.

Signed-off-by Rafael J. Wysocki <[email protected]>

---
 drivers/pci/hotplug/acpiphp_glue.c |   29 ++++++++++++-----------------
 1 file changed, 12 insertions(+), 17 deletions(-)

drivers/pci/hotplug/acpiphp_glue.c +12 ~~-17~~

Index: linux/drivers/pci/hotplug/acpiphp_glue.c
===================================================================
@@ -132,6 +132,18 @@ register_slot(acpi_handle handle, u32 lv
 	if (!acpi_pci_check_ejectable(pbus, handle) && !is_dock_device(handle))
 		return AE_OK;
 
+	pdev = pbus->self;
+	if (pdev && pci_is_pcie(pdev)) {
+		tmp = acpi_find_root_bridge_handle(pdev);
+		if (tmp) {
+			struct acpi_pci_root *root = acpi_pci_find_root(tmp);
+
+			if (root && (root->osc_control_set &
+					OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
+				return AE_OK;
+		}
+	}
+
 	acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
 	device = (adr >> 16) & 0xffff;
 	function = adr & 0xffff;

@@ -459,17 +471,8 @@ static int add_bridge(acpi_handle handle
 {
 	acpi_status status;
 	unsigned long long tmp;
-	struct acpi_pci_root *root;
 	acpi_handle dummy_handle;
 
-	/*
-	 * We shouldn't use this bridge if PCIe native hotplug control has been
-	 * granted by the BIOS for it.
-	 */
-	root = acpi_pci_find_root(handle);
-	if (root && (root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
-		return -ENODEV;
-
 	/* if the bridge doesn't have _STA, we assume it is always there */
 	status = acpi_get_handle(handle, "_STA", &dummy_handle);
 	if (ACPI_SUCCESS(status)) {

@@ -1385,19 +1388,11 @@ static void handle_hotplug_event_func(ac
 static acpi_status
 find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
 {
-	struct acpi_pci_root *root;
 	int *count = (int *)context;
 
 	if (!acpi_is_root_bridge(handle))
 		return AE_OK;
 
-	root = acpi_pci_find_root(handle);
-	if (!root)
-		return AE_OK;
-
-	if (root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL)
-		return AE_OK;
-
 	(*count)++;
 	acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 				    handle_hotplug_event_bridge, NULL);

Rafael J. Wysocki

author

2011-12-12 23:06 UTC #1 lore raw

Hi Jesse,

Quoted 20 lines · Rafael J. Wysocki

From: Rafael J. Wysocki <[email protected]>
Commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a (PCI / ACPI: Make acpiphp ignore root bridges using PCIe native hotplug) added code that made the acpiphp driver completely ignore PCIe root complexes for which the kernel had been granted control of the native PCIe hotplug feature by the BIOS through _OSC. Unfortunately, however, this was a mistake, because on some systems there were PCI bridges supporting PCI (non-PCIe) hotplug under such root complexes and those bridges should have been handled by acpiphp.
For this reason, revert the changes made by the commit mentioned above and make register_slot() in drivers/pci/hotplug/acpiphp_glue.c avoid registering hotplug slots for PCIe ports that belong to root complexes with native PCIe hotplug enabled (which means that the BIOS has granted the kernel control of this feature for the given root complex). This is reported to address the original issue fixed by commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a and to work on the system where that commit broke things.

Quoted 2 lines

Signed-off-by Rafael J. Wysocki <[email protected]>
---

Sorry for the breakage, I clearly should have been more careful here.

Please also revert this commit from your linux-next branch:

http://git.kernel.org/?p=linux/kernel/git/jbarnes/pci.git;a=commit;h=71c50ab7a32968b73b533dd27620eef563ace6b7

as it makes the same mistake and depends on the code being removed by this patch.

Thanks,
Rafael

Jesse Barnes

Applied

2011-12-13 19:19 UTC #2 lore raw

In reply to Rafael J. Wysocki

Quoted 20 lines · On Tue, 13 Dec 2011 00:02:28 +0100 "Rafael J. Wysocki" <[email protected]> wrote:

From: Rafael J. Wysocki <[email protected]>
Commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a (PCI / ACPI: Make acpiphp ignore root bridges using PCIe native hotplug) added code that made the acpiphp driver completely ignore PCIe root complexes for which the kernel had been granted control of the native PCIe hotplug feature by the BIOS through _OSC. Unfortunately, however, this was a mistake, because on some systems there were PCI bridges supporting PCI (non-PCIe) hotplug under such root complexes and those bridges should have been handled by acpiphp.
For this reason, revert the changes made by the commit mentioned above and make register_slot() in drivers/pci/hotplug/acpiphp_glue.c avoid registering hotplug slots for PCIe ports that belong to root complexes with native PCIe hotplug enabled (which means that the BIOS has granted the kernel control of this feature for the given root complex). This is reported to address the original issue fixed by commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a and to work on the system where that commit broke things.

Quoted 2 lines

Signed-off-by Rafael J. Wysocki <[email protected]>
---

Applied to my for-linus branch. I'll probably send to Linus on Thu. or so.

I also rebased the breakage out of linux-next.

Thanks,

Signature · 1 line

Jesse Barnes, Intel Open Source Technology Center

Rafael J. Wysocki

author

2011-12-13 21:06 UTC #3 lore raw

Quoted 23 lines · Jesse Barnes

Quoted 20 lines · On Tue, 13 Dec 2011 00:02:28 +0100 "Rafael J. Wysocki" <[email protected]> wrote:
From: Rafael J. Wysocki <[email protected]>
Commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a (PCI / ACPI: Make acpiphp ignore root bridges using PCIe native hotplug) added code that made the acpiphp driver completely ignore PCIe root complexes for which the kernel had been granted control of the native PCIe hotplug feature by the BIOS through _OSC. Unfortunately, however, this was a mistake, because on some systems there were PCI bridges supporting PCI (non-PCIe) hotplug under such root complexes and those bridges should have been handled by acpiphp.
For this reason, revert the changes made by the commit mentioned above and make register_slot() in drivers/pci/hotplug/acpiphp_glue.c avoid registering hotplug slots for PCIe ports that belong to root complexes with native PCIe hotplug enabled (which means that the BIOS has granted the kernel control of this feature for the given root complex). This is reported to address the original issue fixed by commit 0d52f54e2ef64c189dedc332e680b2eb4a34590a and to work on the system where that commit broke things.

Quoted 7 lines

Quoted 2 lines
Signed-off-by Rafael J. Wysocki <[email protected]>
---
Applied to my for-linus branch. I'll probably send to Linus on Thu. or so.
I also rebased the breakage out of linux-next.

Thanks a lot!

Rafael