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    SubjectRe: [PATCH v2] staging: comedi: resolve section mismatch in s626
    On Tue Apr 10 12, Greg KH wrote:
    > On Mon, Apr 02, 2012 at 11:48:54AM +0100, Ian Abbott wrote:
    > > On 2012-03-19 23:26, Greg KH wrote:
    > > >On Mon, Mar 19, 2012 at 03:46:49PM -0700, Gerard Snitselaar wrote:
    > > >>On Mon, Mar 19, 2012 at 09:43:25AM -0700, Gerard Snitselaar wrote:
    > > >>>On Mon, Mar 19, 2012 at 09:31:03AM -0700, Greg KH wrote:
    > > >>>>
    > > >>>>Ick, why is this loop even needed? We are only here if the pci device
    > > >>>>is present in the system so this shouldn't be needed at all, right?
    > > >>>>
    > > >>>>Or is this a bit more complex than I am making it out to be?
    > > >>>>
    > > >>>>greg k-h
    > > >>>
    > > >>>Most likely not. I will take a look at some of the other drivers in
    > > >>>comedi and see how the attach code looks there. I believe the code
    > > >>>section in hpdi_attach() was written by the same person. Unfortunately
    > > >>>I don't have a device to actually play around and see what changes are
    > > >>>doing.
    > > >>>
    > > >>
    > > >>I looked at this a bit more. It looks like they lose visibility to the
    > > >>pci_dev structure.
    > > >>
    > > >>*_probe()
    > > >> comedi_pci_auto_config() pci_dev
    > > >> comedi_auto_config() pci_dev->dev
    > > >> comedi_device_attach() ??
    > > >> driv->attach() ??<= iterate through pci devices.
    > > >>
    > > >>Most of the examples I have looked at so far use for_each_pci_dev() to
    > > >>find the device, and s626 shortcuts it a bit by directly making calls
    > > >>to pci_get_subsys() with specific ids. They all verify they have the
    > > >>right device by checking the bus and slot that are grabbed from the
    > > >>pci_dev in comedi_pci_auto_config() and passed down.
    > > >
    > > >Ugh, surely there's a way to keep the pci dev through the
    > > >comedi_device_attach() call, right?
    > >
    > > comedi_device_attach() is also called for the COMEDI_DEVCONFIG ioctl
    > > for "manually" configuring a comedi device, and that has no idea
    > > about struct pci_dev, etc.
    > >
    > > I recently posted a series of patches that allows lower-level comedi
    > > drivers to supply separate hooks for auto-configuring PCI devices or
    > > USB devices without abusing the old "manual configuration" code
    > > paths, see <http://driverdev.linuxdriverproject.org/pipermail/devel/2012-March/025331.html>.
    > >
    > > The old loop that searches the PCI bus is still needed for the
    > > "manual configuration" code path.
    >
    > So, now that I've applied your patches, this patch isn't needed anymore,
    > right? Or should it be reworked to use the new interfaces?
    >
    > thanks,
    >
    > greg k-h
    >

    I'd say drop my patch and if there is still a mismatch problem it can
    probably be resolved in a better way.

    gerard



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