Commit b07f2ebc authored by Yinghai Lu's avatar Yinghai Lu Committed by Jesse Barnes
Browse files

PCI: add a PCI resource reallocation config option

Add a new config option, PCI_REALLOC_ENABLE_AUTO, which will
automatically try to re-allocate PCI resources if PCI_IOV support is
enabled and the SR-IOV resources are unassigned.  Behavior can still be
controlled using the pci=realloc= parameter.

-v2: According to Jesse, adding one CONFIG option for distribution to
     disable it or enable it.
-v3: update Kconfig text (jbarnes)

Signed-off-by: default avatarYinghai Lu <>
Signed-off-by: default avatarJesse Barnes <>
parent eb572e7c
......@@ -31,6 +31,19 @@ config PCI_DEBUG
When in doubt, say N.
bool "Enable PCI resource re-allocation detection"
depends on PCI
Say Y here if you want the PCI core to detect if PCI resource
re-allocation needs to be enabled. You can always use pci=realloc=on
or pci=realloc=off to override it. Note this feature is a no-op
unless PCI_IOV support is also enabled; in that case it will
automatically re-allocate PCI resources if SR-IOV BARs have not
been allocated by the BIOS.
When in doubt, say N.
config PCI_STUB
tristate "PCI Stub driver"
depends on PCI
......@@ -1294,6 +1294,31 @@ static bool __init pci_realloc_enabled(void)
return pci_realloc_enable >= user_enabled;
static void __init pci_realloc_detect(void)
struct pci_dev *dev = NULL;
if (pci_realloc_enable != undefined)
for_each_pci_dev(dev) {
int i;
struct resource *r = &dev->resource[i];
/* Not assigned, or rejected by kernel ? */
if (r->flags && !r->start) {
pci_realloc_enable = auto_enabled;
* first try will not touch pci bridge res
* second and later try will clear small leaf bridge res
......@@ -1315,6 +1340,7 @@ pci_assign_unassigned_resources(void)
int pci_try_num = 1;
/* don't realloc if asked to do so */
if (pci_realloc_enabled()) {
int max_depth = pci_get_max_depth();
......@@ -1349,6 +1375,8 @@ again:
if (tried_times >= pci_try_num) {
if (pci_realloc_enable == undefined)
printk(KERN_INFO "Some PCI device resources are unassigned, try booting with pci=realloc\n");
else if (pci_realloc_enable == auto_enabled)
printk(KERN_INFO "Automatically enabled pci realloc, if you have problem, try booting with pci=realloc=off\n");
goto enable_and_dump;
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment