Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / Documentation / powerpc / eeh-pci-error-recovery.txt

diff --git a/Documentation/powerpc/eeh-pci-error-recovery.txt b/Documentation/powerpc/eeh-pci-error-recovery.txt
index 2bfe71b..3764dd4 100644 (file)
--- a/Documentation/powerpc/eeh-pci-error-recovery.txt
+++ b/Documentation/powerpc/eeh-pci-error-recovery.txt
@@ -115,13 +115,13 @@ Current PPC64 Linux EEH Implementation
 At this time, a generic EEH recovery mechanism has been implemented,
 so that individual device drivers do not need to be modified to support
 EEH recovery.  This generic mechanism piggy-backs on the PCI hotplug
-infrastructure,  and percolates events up through the hotplug/udev
+infrastructure,  and percolates events up through the userspace/udev
 infrastructure.  Followiing is a detailed description of how this is
 accomplished.
 
 EEH must be enabled in the PHB's very early during the boot process,
 and if a PCI slot is hot-plugged. The former is performed by
-eeh_init() in arch/ppc64/kernel/eeh.c, and the later by
+eeh_init() in arch/powerpc/platforms/pseries/eeh.c, and the later by
 drivers/pci/hotplug/pSeries_pci.c calling in to the eeh.c code.
 EEH must be enabled before a PCI scan of the device can proceed.
 Current Power5 hardware will not work unless EEH is enabled;
@@ -133,8 +133,8 @@ error.  Given an arbitrary address, the routine
 pci_get_device_by_addr() will find the pci device associated
 with that address (if any).
 
-The default include/asm-ppc64/io.h macros readb(), inb(), insb(),
-etc. include a check to see if the the i/o read returned all-0xff's.
+The default include/asm-powerpc/io.h macros readb(), inb(), insb(),
+etc. include a check to see if the i/o read returned all-0xff's.
 If so, these make a call to eeh_dn_check_failure(), which in turn
 asks the firmware if the all-ff's value is the sign of a true EEH
 error.  If it is not, processing continues as normal.  The grand
@@ -143,11 +143,12 @@ seen in /proc/ppc64/eeh (subject to change).  Normally, almost
 all of these occur during boot, when the PCI bus is scanned, where
 a large number of 0xff reads are part of the bus scan procedure.
 
-If a frozen slot is detected, code in arch/ppc64/kernel/eeh.c will
-print a stack trace to syslog (/var/log/messages).  This stack trace
-has proven to be very useful to device-driver authors for finding
-out at what point the EEH error was detected, as the error itself
-usually occurs slightly beforehand.
+If a frozen slot is detected, code in 
+arch/powerpc/platforms/pseries/eeh.c will print a stack trace to 
+syslog (/var/log/messages).  This stack trace has proven to be very 
+useful to device-driver authors for finding out at what point the EEH 
+error was detected, as the error itself usually occurs slightly 
+beforehand.
 
 Next, it uses the Linux kernel notifier chain/work queue mechanism to
 allow any interested parties to find out about the failure.  Device
@@ -172,7 +173,7 @@ A handler for the EEH notifier_block events is implemented in
 drivers/pci/hotplug/pSeries_pci.c, called handle_eeh_events().
 It saves the device BAR's and then calls rpaphp_unconfig_pci_adapter().
 This last call causes the device driver for the card to be stopped,
-which causes hotplug events to go out to user space. This triggers
+which causes uevents to go out to user space. This triggers
 user-space scripts that might issue commands such as "ifdown eth0"
 for ethernet cards, and so on.  This handler then sleeps for 5 seconds,
 hoping to give the user-space scripts enough time to complete.
@@ -258,29 +259,30 @@ rpa_php_unconfig_pci_adapter() {             // in rpaphp_pci.c
     calls
     pci_destroy_dev (struct pci_dev *) {
       calls
-      device_unregister (&dev->dev) {      // in /drivers/base/core.c
+      device_unregister (&dev->dev) {        // in /drivers/base/core.c
         calls
-        device_del(struct device * dev) {  // in /drivers/base/core.c
+        device_del(struct device * dev) {    // in /drivers/base/core.c
           calls
-          kobject_del() {                  //in /libs/kobject.c
+          kobject_del() {                    //in /libs/kobject.c
             calls
-            kobject_hotplug() {            // in /libs/kobject.c
+            kobject_uevent() {               // in /libs/kobject.c
               calls
-              kset_hotplug() {             // in /lib/kobject.c
+              kset_uevent() {                // in /lib/kobject.c
                 calls
-                kset->hotplug_ops->hotplug() which is really just
+                kset->uevent_ops->uevent()   // which is really just
                 a call to
-                dev_hotplug() {           // in /drivers/base/core.c
+                dev_uevent() {               // in /drivers/base/core.c
                   calls
-                  dev->bus->hotplug() which is really just a call to
-                  pci_hotplug () {      // in drivers/pci/hotplug.c
+                  dev->bus->uevent() which is really just a call to
+                  pci_uevent () {            // in drivers/pci/hotplug.c
                     which prints device name, etc....
                  }
                }
-               then kset_hotplug() calls
-                call_usermodehelper () with
-                   argv[0]=hotplug_path[] which is "/sbin/hotplug"
-             --> event to userspace,
+               then kobject_uevent() sends a netlink uevent to userspace
+               --> userspace uevent
+               (during early boot, nobody listens to netlink events and
+               kobject_uevent() executes uevent_helper[], which runs the
+               event process /sbin/hotplug)
            }
          }
          kobject_del() then calls sysfs_remove_dir(), which would