vserver 1.9.3

[linux-2.6.git] / Documentation / pci.txt

diff --git a/Documentation/pci.txt b/Documentation/pci.txt
index d30dc10..a1a2bd5 100644 (file)
--- a/Documentation/pci.txt
+++ b/Documentation/pci.txt
@@ -25,6 +25,7 @@ on (either the old or the new way), it needs to perform the following steps:
        Discover resources (addresses and IRQ numbers) provided by the device
        Allocate these resources
        Communicate with the device
+       Disable the device
 
 Most of these topics are covered by the following sections, for the rest
 look at <linux/pci.h>, it's hopefully well commented.
@@ -162,12 +163,13 @@ You must eventually (possibly at module unload) decrement the reference
 count on these devices by calling pci_dev_put().
 
 
-3. Enabling devices
-~~~~~~~~~~~~~~~~~~~
+3. Enabling and disabling devices
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Before you do anything with the device you've found, you need to enable
 it by calling pci_enable_device() which enables I/O and memory regions of
-the device, assigns missing resources if needed and wakes up the device
-if it was in suspended state. Please note that this function can fail.
+the device, allocates an IRQ if necessary, assigns missing resources if
+needed and wakes up the device if it was in suspended state. Please note
+that this function can fail.
 
    If you want to use the device in bus mastering mode, call pci_set_master()
 which enables the bus master bit in PCI_COMMAND register and also fixes
@@ -179,6 +181,12 @@ and also ensures that the cache line size register is set correctly.
 Make sure to check the return value of pci_set_mwi(), not all architectures
 may support Memory-Write-Invalidate.
 
+   If your driver decides to stop using the device (e.g., there was an
+error while setting it up or the driver module is being unloaded), it
+should call pci_disable_device() to deallocate any IRQ resources, disable
+PCI bus-mastering, etc.  You should not do anything with the device after
+calling pci_disable_device().
+
 4. How to access PCI config space
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    You can use pci_(read|write)_config_(byte|word|dword) to access the config