Re: [git pull] PCI fixes

Yinghai Lu
2011-06-25T00:18:28Z

On 06/24/2011 05:00 PM, Jesse Barnes wrote:
> On Fri, 24 Jun 2011 15:56:42 -0700
> Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
>>
>>
>>
>> Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
>>>
>>> How about a boot param? We've done similar things for _CRS, and it
>>> might give Yinghai and Ram some more flexibility in improving our
>>> dynamic resource allocation before enabling it again (if ever).
>>
>> I'm OK with that, but then I'd suggest against the currently not yet merged series that doesn't seem to work anyway...
>>
>> IOW, just a simple patch that disables the resource re-allocation, and enables it with some command line option.
>
> Ok sounds good, thanks.

please check the draft one, not sure if you like
pci=try=2
or
pci=reallocate_bridge

[PATCH] pci: disable pci trying to reallocate pci bridge by default.

| PCI: update bridge resources to get more big ranges when allocating space (again)
| da7822e5ad71ec9b745b412639f1e5e0ba795a20

still too risky and cause some systems have problem.

Disable reallocating feature, So other user could use command line enable it
to enable it with "pci=try=2"

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
Documentation/kernel-parameters.txt | 6 ++++++
drivers/pci/pci.c | 4 ++++
drivers/pci/pci.h | 2 ++
drivers/pci/setup-bus.c | 15 +++++++++------
4 files changed, 21 insertions(+), 6 deletions(-)

Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -1980,6 +1980,12 @@ bytes respectively. Such letter suffixes
for broken drivers that don't call it.
skip_isa_align [X86] do not align io start addr, so can
handle more pci cards
+ try=n set the pci_try_num to reallocate the pci bridge resource
+ 1: default
+ 2: will set the num to max_depth, and try to reallocate res
+ to get big range for the bridge. assume the pci peer root
+ resource is right from _CRS or from hostbridge pci reg
+ reading out.
firmware [ARM] Do not re-enumerate the bus but instead
just use the configuration from the
bootloader. This is currently used on
Index: linux-2.6/drivers/pci/pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -3485,6 +3485,10 @@ static int __init pci_setup(char *str)
pci_no_aer();
} else if (!strcmp(str, "nodomains")) {
pci_no_domains();
+ } else if (!strncmp(str, "try=", 4)) {
+ int try_num = memparse(str + 4, &str);
+ if (try_num > 0)
+ pci_try_num = try_num;
} else if (!strncmp(str, "cbiosize=", 9)) {
pci_cardbus_io_size = memparse(str + 9, &str);
} else if (!strncmp(str, "cbmemsize=", 10)) {
Index: linux-2.6/drivers/pci/pci.h
===================================================================
--- linux-2.6.orig/drivers/pci/pci.h
+++ linux-2.6/drivers/pci/pci.h
@@ -223,6 +223,8 @@ static inline int pci_ari_enabled(struct
return bus->self && bus->self->ari_enabled;
}

+extern int pci_try_num;
+
#ifdef CONFIG_PCI_QUIRKS
extern int pci_is_reassigndev(struct pci_dev *dev);
resource_size_t pci_specified_resource_alignment(struct pci_dev *dev);
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
@@ -1030,6 +1030,7 @@ static int __init pci_get_max_depth(void
* second and later try will clear small leaf bridge res
* will stop till to the max deepth if can not find good one
*/
+int pci_try_num = 1;
void __init
pci_assign_unassigned_resources(void)
{
@@ -1042,16 +1043,18 @@ pci_assign_unassigned_resources(void)
unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
IORESOURCE_PREFETCH;
unsigned long failed_type;
- int max_depth = pci_get_max_depth();
- int pci_try_num;
-

head.next = NULL;
add_list.next = NULL;

- pci_try_num = max_depth + 1;
- printk(KERN_DEBUG "PCI: max bus depth: %d pci_try_num: %d\n",
- max_depth, pci_try_num);
+ if (pci_try_num > 1) {
+ int max_depth = pci_get_max_depth();
+
+ if (max_depth + 1 > pci_try_num)
+ pci_try_num = max_depth + 1;
+ printk(KERN_DEBUG "PCI: max bus depth: %d pci_try_num: %d\n",
+ max_depth, pci_try_num);
+ }

again:
/* Depth first, calculate sizes and alignments of all