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Message-ID: <4C2BCC5D.3080402@kernel.org>
Date: Wed, 30 Jun 2010 15:59:41 -0700
From: Yinghai Lu <yinghai@...nel.org>
To: Ram Pai <linuxram@...ibm.com>,
Jesse Barnes <jbarnes@...tuousgeek.org>,
Linus Torvalds <torvalds@...ux-foundation.org>
CC: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
clemens@...isch.de
Subject: Re: [RFC PATCH 1/1] PCI: skip release and reallocation of io port
resources
On 06/30/2010 02:15 PM, Ram Pai wrote:
> PCI: skip release and reallocation of io port resources
>
> git commit 977d17bb1749517b353874ccdc9b85abc7a58c2a
> released and reallocated all resources, ioport and memory, when
> allocation of any resource of any type failed. This caused
> failure to reallocate fragile io port resources, as reported in
> https://bugzilla.kernel.org/show_bug.cgi?id=15960
>
> The problem was solved by reverting the commit, through
> git commit 769d9968e42c995eaaf61ac5583d998f32e0769a.
>
> However reverting the original patch fails MMIO resource allocation
> for SRIOV PCI-Bars on some platforms. Especially on platforms
> where the BIOS is unaware of SRIOV resource BARs.
>
> The following code, an idea proposed by Yinghai Lu, skips release
> and re-allocation of io port resources if its allocation has
> not failed in the first place.
>
> This patch applies on top of patch corresponding to
> git commit 977d17bb1749517b353874ccdc9b85abc7a58c2a
>
for safe all, i would suggest
1. put back
977d17bb1749517b353874ccdc9b85abc7a58c2a
2. and apply following patch.
[PATCH] pci: disable pci trying to reallocate pci bridge by default.
it broken Linus's Nouveau
bisected:to commit 977d17bb17
| PCI: update bridge resources to get more big ranges in PCI assign unssigned
so try disable it by default.
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
Documentation/kernel-parameters.txt | 6 ++++++
drivers/pci/pci.c | 4 ++++
drivers/pci/pci.h | 2 ++
drivers/pci/setup-bus.c | 14 +++++++++-----
4 files changed, 21 insertions(+), 5 deletions(-)
Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -2009,6 +2009,12 @@ and is between 256 and 4096 characters.
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
@@ -2983,6 +2983,10 @@ 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
@@ -212,6 +212,8 @@ 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
@@ -869,6 +869,7 @@ 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)
{
@@ -879,14 +880,17 @@ 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;
- 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
--
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