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[PATCH] PCI: clean up pci documentation to be more specific
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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>
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Grant Grundler authored and Greg Kroah-Hartman committed Jun 21, 2006
1 parent f7e6600 commit 733a7fe
Showing 1 changed file with 11 additions and 3 deletions.
14 changes: 11 additions & 3 deletions Documentation/pci.txt
Original file line number Diff line number Diff line change
Expand Up @@ -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).
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