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PCI: conditional resource-reallocation through kernel parameter pci=realloc

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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>
This commit is contained in:
Ram Pai 2011-07-07 11:19:10 -07:00 committed by Jesse Barnes
parent a2fa83faf4
commit f483d3923d
4 changed files with 21 additions and 0 deletions
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2
Documentation/kernel-parameters.txt
View file

@ -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.

2
drivers/pci/pci.c
View file

@ -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)) {

2
drivers/pci/pci.h
View file

@ -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;

15
drivers/pci/setup-bus.c
View file

@ -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;