From b3c32c4f9565f93407921c0d8a4458042eb8998e Mon Sep 17 00:00:00 2001
From: Huang Ying <ying.huang@intel.com>
Date: Thu, 25 Oct 2012 09:36:03 +0800
Subject: PCI/PM: Fix proc config reg access for D3cold and bridge suspending
In https://bugzilla.kernel.org/show_bug.cgi?id=48981
Peter reported that /proc/bus/pci/??/??.? does not work for 3.6.
This is because the device configuration space registers are
not accessible if the corresponding parent bridge is suspended or
the device is put into D3cold state.
This is the same as /sys/bus/pci/devices/0000:??:??.?/config access
issue. So the function used to solve sysfs issue is used to solve
this issue.
This patch moves pci_config_pm_runtime_get()/_put() from pci/pci-sysfs.c
to pci/pci.c and makes them extern so they can be used by both the
sysfs and proc paths.
[bhelgaas: changelog, references, reporters]
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=48981
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=49031
Reported-by: Forrest Loomis <cybercyst@gmail.com>
Reported-by: Peter <lekensteyn@gmail.com>
Reported-by: Micael Dias <kam1kaz3@gmail.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: stable@vger.kernel.org # v3.6+
---
drivers/pci/proc.c | 8 ++++++++
1 file changed, 8 insertions(+)
(limited to 'drivers/pci/proc.c')
diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
index eb907a8faf2..9b8505ccc56 100644
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -76,6 +76,8 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
if (!access_ok(VERIFY_WRITE, buf, cnt))
return -EINVAL;
+ pci_config_pm_runtime_get(dev);
+
if ((pos & 1) && cnt) {
unsigned char val;
pci_user_read_config_byte(dev, pos, &val);
@@ -121,6 +123,8 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
cnt--;
}
+ pci_config_pm_runtime_put(dev);
+
*ppos = pos;
return nbytes;
}
@@ -146,6 +150,8 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
if (!access_ok(VERIFY_READ, buf, cnt))
return -EINVAL;
+ pci_config_pm_runtime_get(dev);
+
if ((pos & 1) && cnt) {
unsigned char val;
__get_user(val, buf);
@@ -191,6 +197,8 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
cnt--;
}
+ pci_config_pm_runtime_put(dev);
+
*ppos = pos;
i_size_write(ino, dp->size);
return nbytes;
--
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