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authorRam Pai <linuxram@us.ibm.com>2011-07-07 11:19:10 -0700
committerJesse Barnes <jbarnes@virtuousgeek.org>2011-07-08 15:49:20 -0700
commitf483d3923dc3a6394c483e28ccb3fe700bdf399e (patch)
treeef487babd0ef104e1fa8323c23050d66096c0f3a
parenta2fa83faf47b514ab947cea916d3691b66525073 (diff)
downloadlinux-linaro-f483d3923dc3a6394c483e28ccb3fe700bdf399e.tar.gz
PCI: conditional resource-reallocation through kernel parameter pci=realloc
Multiple attempts to dynamically reallocate pci resources have unfortunately lead to regressions. Though we continue to fix the regressions and fine tune the dynamic-reallocation behavior, we have not reached a acceptable state yet. This patch provides a interim solution. It disables dynamic reallocation by default, but adds the ability to enable it through pci=realloc kernel command line parameter. Tested-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
-rw-r--r--Documentation/kernel-parameters.txt2
-rw-r--r--drivers/pci/pci.c2
-rw-r--r--drivers/pci/pci.h2
-rw-r--r--drivers/pci/setup-bus.c15
4 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index fd248a31821..aa47be71df4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2015,6 +2015,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
the default.
off: Turn ECRC off
on: Turn ECRC on.
+ realloc reallocate PCI resources if allocations done by BIOS
+ are erroneous.
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 2c5b9b99127..692671b1166 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3483,6 +3483,8 @@ static int __init pci_setup(char *str)
pci_no_msi();
} else if (!strcmp(str, "noaer")) {
pci_no_aer();
+ } else if (!strncmp(str, "realloc", 7)) {
+ pci_realloc();
} else if (!strcmp(str, "nodomains")) {
pci_no_domains();
} else if (!strncmp(str, "cbiosize=", 9)) {
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 731e20265ac..3a39bf1f1e2 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -146,6 +146,8 @@ static inline void pci_no_msi(void) { }
static inline void pci_msi_init_pci_dev(struct pci_dev *dev) { }
#endif
+extern void pci_realloc(void);
+
static inline int pci_no_d1d2(struct pci_dev *dev)
{
unsigned int parent_dstates = 0;
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 1e9e5a5b8c8..9995842e45b 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -47,6 +47,13 @@ struct resource_list_x {
(head)->next = NULL; \
} while (0)
+int pci_realloc_enable = 0;
+#define pci_realloc_enabled() pci_realloc_enable
+void pci_realloc(void)
+{
+ pci_realloc_enable = 1;
+}
+
/**
* add_to_list() - add a new resource tracker to the list
* @head: Head of the list
@@ -1025,6 +1032,7 @@ static int __init pci_get_max_depth(void)
return depth;
}
+
/*
* first try will not touch pci bridge res
* second and later try will clear small leaf bridge res
@@ -1068,6 +1076,13 @@ again:
/* any device complain? */
if (!head.next)
goto enable_and_dump;
+
+ /* don't realloc if asked to do so */
+ if (!pci_realloc_enabled()) {
+ free_list(resource_list_x, &head);
+ goto enable_and_dump;
+ }
+
failed_type = 0;
for (list = head.next; list;) {
failed_type |= list->flags;