Merge branch 'upstream-greg' of gregkh@master.kernel.org:/pub/scm/linux/kernel/git...

[pandora-kernel.git] / Documentation / pci.txt

diff --git a/Documentation/pci.txt b/Documentation/pci.txt
index 711210b..2b395e4 100644 (file)
--- a/Documentation/pci.txt
+++ b/Documentation/pci.txt
@@ -213,11 +213,19 @@ 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.
-
-   All interrupt handlers should be registered with SA_SHIRQ and use the devid
+   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 IRQF_SHARED and use the devid
 to map IRQs to devices (remember that all PCI interrupts are shared).
 
 
@@ -259,7 +267,17 @@ on the bus need to be capable of doing it, so this is something which needs
 to be handled by platform and generic code, not individual drivers.
 
 
-8. Obsolete functions
+8. Vendor and device identifications
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+For the future, let's avoid adding device ids to include/linux/pci_ids.h.
+
+PCI_VENDOR_ID_xxx for vendors, and a hex constant for device ids.
+
+Rationale:  PCI_VENDOR_ID_xxx constants are re-used, but device ids are not.
+    Further, device ids are arbitrary hex numbers, normally used only in a
+    single location, the pci_device_id table.
+
+9. Obsolete functions
 ~~~~~~~~~~~~~~~~~~~~~
 There are several functions which you might come across when trying to
 port an old driver to the new PCI interface.  They are no longer present