[PATCH RFC v4 09/21] PCI: Mark immovable BARs with PCI_FIXED

David Laight David.Laight at ACULAB.COM
Thu Mar 28 04:03:52 AEDT 2019

From: Bjorn Helgaas
> Sent: 26 March 2019 20:29
> On Mon, Mar 11, 2019 at 04:31:10PM +0300, Sergey Miroshnichenko wrote:
> > If a PCIe device driver doesn't yet have support for movable BARs,
> > mark device's BARs with IORESOURCE_PCI_FIXED.
> I'm hesitant about using IORESOURCE_PCI_FIXED for this purpose.  That
> was originally added to describe resources that can not be changed
> because they're hardwired in the device, e.g., legacy resources and
> Enhanced Allocation resources.
> In general, I think the bits in res->flags should tell us things about
> the hardware.  This particular use would be something about the
> *driver*, and I think we should figure that out by looking at
> dev->driver.

There will also be drivers that don't support BARs being moved,
but may be in a state (ie not actually open) where they can go
through a remove-rescan sequence to allow the BAR be moved.

This might even be true if the open count is non-zero.


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