[PATCH] PCI: clean up pci documentation to be more specific

On Thu, Jun 01, 2006 at 02:46:11AM -0700, Rajesh Shah wrote:
> This patch assumes that pci_request_region() will always be called
> after pci_enable_device() and pci_release_region() will always
> be called before pci_disable_device(). We cannot make this
> assumption,since it's perfectly legal to disable a device
> first and then release it's regions. So, I think that patch
> needs to change.

Patch below clarifies comments in Documentation/pci.txt.

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/Documentation/pci.txt b/Documentation/pci.txt
index 66bbbf1..3242e5c 100644 (file)
--- a/Documentation/pci.txt
+++ b/Documentation/pci.txt
@@ -213,9 +213,17 @@ have been remapped by the kernel.
 
    See Documentation/IO-mapping.txt for how to access device memory.
 
-   You still need to call request_region() for I/O regions and
-request_mem_region() for memory regions to make sure nobody else is using the
-same device.
+   The device driver needs to call pci_request_region() to make sure
+no other device is already using the same resource. The driver is expected
+to determine MMIO and IO Port resource availability _before_ calling
+pci_enable_device().  Conversely, drivers should call pci_release_region()
+_after_ calling pci_disable_device(). The idea is to prevent two devices
+colliding on the same address range.
+
+Generic flavors of pci_request_region() are request_mem_region()
+(for MMIO ranges) and request_region() (for IO Port ranges).
+Use these for address resources that are not described by "normal" PCI
+interfaces (e.g. BAR).
 
    All interrupt handlers should be registered with SA_SHIRQ and use the devid
 to map IRQs to devices (remember that all PCI interrupts are shared).