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Date: Fri, 06 May 2011 13:22:04 -0700
From: Yinghai Lu <yinghai@...nel.org>
To: Ram Pai <linuxram@...ibm.com>
CC: Jesse Barnes <jbarnes@...tuousgeek.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Subject: Re: [PATCH] pci: Check bridge resources after resource allocation.
On 05/06/2011 01:12 AM, Ram Pai wrote:
> On Thu, May 05, 2011 at 12:24:22AM -0700, Yinghai Lu wrote:
>>
>> During pci remove/rescan testing found:
>>
>> [ 541.141614] pci 0000:c0:03.0: PCI bridge to [bus c4-c9]
>> [ 541.141965] pci 0000:c0:03.0: bridge window [io 0x1000-0x0fff]
>> [ 541.159181] pci 0000:c0:03.0: bridge window [mem 0xf0000000-0xf00fffff]
>> [ 541.159540] pci 0000:c0:03.0: bridge window [mem 0xfc180000000-0xfc197ffffff 64bit pref]
>> [ 541.179374] pci 0000:c0:03.0: device not available (can't reserve [io 0x1000-0x0fff])
>> [ 541.199198] pci 0000:c0:03.0: Error enabling bridge (-22), continuing
>> [ 541.199202] pci 0000:c0:03.0: enabling bus mastering
>> [ 541.199209] pci 0000:c0:03.0: setting latency timer to 64
>> [ 541.199917] pcieport 0000:c0:03.0: device not available (can't reserve [io 0x1000-0x0fff])
>> [ 541.199963] pcieport: probe of 0000:c0:03.0 failed with error -22
>>
>> This bug was uncovered by commit
>> | commit c8adf9a3e873eddaaec11ac410a99ef6b9656938
>> | Author: Ram Pai <linuxram@...ibm.com>
>> | Date: Mon Feb 14 17:43:20 2011 -0800
>> |
>> | PCI: pre-allocate additional resources to devices only after successful allo
>> cation of essential resources.
>>
>> After that commit, pci_hotplug_io_size is changed to additional_io_size from minium size. So it will not get into failed list, and will not be reset there.
>>
>> The root cause is: pci_bridge_check_ranges will set RESOURCE_IO flag for pci
>> bridge, and later if children does not need to IO resource. those bridge
>> resources will not need to be allocated. but flags still there.
>>
>> Add pci_bridge_check_resources() to close the loop.
>
> How about resetting the resource in adjust_resources_sorted() if call to
> adjust_resource() fails, and the resource is left with zero size?
>
> Something like this:
>
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 8e73abf..77e8454 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -157,8 +157,11 @@ static void adjust_resources_sorted(struct resource_list_x *add_head,
> if(pci_assign_resource(list->dev, idx))
> reset_resource(res);
> } else if (add_size) {
> - adjust_resource(res, res->start,
> - resource_size(res) + add_size);
> + if (adjust_resource(res, res->start,
> + resource_size(res) + add_size) &&
> + !resource_size(res)) {
> + reset_resource(res);
> + }
> }
> out:
> tmp = list;
>
>
no, adjust_resource will not change resource size to zero.
also pci_assign_unassigned_bridge_resources ==> pci_bus_size_bridges, it will not take add_list.
following patch works too.
[PATCH] pci: Using add_list in pcie hotplug path.
During pci remove/rescan testing found:
[ 541.141614] pci 0000:c0:03.0: PCI bridge to [bus c4-c9]
[ 541.141965] pci 0000:c0:03.0: bridge window [io 0x1000-0x0fff]
[ 541.159181] pci 0000:c0:03.0: bridge window [mem 0xf0000000-0xf00fffff]
[ 541.159540] pci 0000:c0:03.0: bridge window [mem 0xfc180000000-0xfc197ffffff 64bit pref]
[ 541.179374] pci 0000:c0:03.0: device not available (can't reserve [io 0x1000-0x0fff])
[ 541.199198] pci 0000:c0:03.0: Error enabling bridge (-22), continuing
[ 541.199202] pci 0000:c0:03.0: enabling bus mastering
[ 541.199209] pci 0000:c0:03.0: setting latency timer to 64
[ 541.199917] pcieport 0000:c0:03.0: device not available (can't reserve [io 0x1000-0x0fff])
[ 541.199963] pcieport: probe of 0000:c0:03.0 failed with error -22
This bug was uncovered by commit
| commit c8adf9a3e873eddaaec11ac410a99ef6b9656938
| Author: Ram Pai <linuxram@...ibm.com>
| Date: Mon Feb 14 17:43:20 2011 -0800
|
| PCI: pre-allocate additional resources to devices only after successful allo
cation of essential resources.
After that commit, pci_hotplug_io_size is changed to additional_io_size from minium size.
So it will not get into failed list, and will not be reset there.
It turns out we need to add_head for those calling.
So those resource get reset properly.
after patch, will get right result:
[ 621.206655] pci 0000:c0:03.0: PCI bridge to [bus c4-c9]
[ 621.206912] pci 0000:c0:03.0: bridge window [io disabled]
[ 621.226594] pci 0000:c0:03.0: bridge window [mem 0xf0000000-0xf00fffff]
[ 621.226904] pci 0000:c0:03.0: bridge window [mem 0xfc180000000-0xfc197ffffff 64bit pref]
[ 621.247012] pci 0000:c0:03.0: enabling bus mastering
[ 621.247275] pci 0000:c0:03.0: setting latency timer to 64
[ 621.267656] pcieport 0000:c0:03.0: setting latency timer to 64
[ 621.268134] pcieport 0000:c0:03.0: irq 160 for MSI/MSI-X
[ 621.286832] pcieport 0000:c0:03.0: Signaling PME through PCIe PME interrupt
[ 621.306360] pci 0000:c4:00.0: Signaling PME through PCIe PME interrupt
[ 621.306684] pcie_pme 0000:c0:03.0:pcie01: service driver pcie_pme loaded
[ 621.326512] aer 0000:c0:03.0:pcie02: service driver aer loaded
[ 621.326911] pciehp 0000:c0:03.0:pcie04: Hotplug Controller:
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
drivers/pci/setup-bus.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
Index: linux-2.6/drivers/pci/setup-bus.c
===================================================================
--- linux-2.6.orig/drivers/pci/setup-bus.c
+++ linux-2.6/drivers/pci/setup-bus.c
@@ -217,13 +217,14 @@ static void __assign_resources_sorted(st
}
static void pdev_assign_resources_sorted(struct pci_dev *dev,
+ struct resource_list_x *add_head,
struct resource_list_x *fail_head)
{
struct resource_list head;
head.next = NULL;
__dev_sort_resources(dev, &head);
- __assign_resources_sorted(&head, NULL, fail_head);
+ __assign_resources_sorted(&head, add_head, fail_head);
}
@@ -852,17 +853,19 @@ void __ref pci_bus_assign_resources(cons
EXPORT_SYMBOL(pci_bus_assign_resources);
static void __ref __pci_bridge_assign_resources(const struct pci_dev *bridge,
+ struct resource_list_x *add_head,
struct resource_list_x *fail_head)
{
struct pci_bus *b;
- pdev_assign_resources_sorted((struct pci_dev *)bridge, fail_head);
+ pdev_assign_resources_sorted((struct pci_dev *)bridge,
+ add_head, fail_head);
b = bridge->subordinate;
if (!b)
return;
- __pci_bus_assign_resources(b, NULL, fail_head);
+ __pci_bus_assign_resources(b, add_head, fail_head);
switch (bridge->class >> 8) {
case PCI_CLASS_BRIDGE_PCI:
@@ -1129,6 +1132,8 @@ enable_and_dump:
void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
{
struct pci_bus *parent = bridge->subordinate;
+ struct resource_list_x add_list; /* list of resources that
+ want additional resources */
int tried_times = 0;
struct resource_list_x head, *list;
int retval;
@@ -1136,11 +1141,12 @@ void pci_assign_unassigned_bridge_resour
IORESOURCE_PREFETCH;
head.next = NULL;
+ add_list.next = NULL;
again:
- pci_bus_size_bridges(parent);
- __pci_bridge_assign_resources(bridge, &head);
-
+ __pci_bus_size_bridges(parent, &add_list);
+ __pci_bridge_assign_resources(bridge, &add_list, &head);
+ BUG_ON(add_list.next);
tried_times++;
if (!head.next)
--
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