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    SubjectRe: PnP model
    On Tue, 4 Feb 2003, Russell King wrote:

    > On Mon, Feb 03, 2003 at 08:43:25PM +0000, Adam Belay wrote:
    > > In many cases, Auto configuration can be better then manual configuration.
    > > 1.) The auto configuration engine in my patch is able to resolve almost any
    > > resource conflict and provides the greatest chance for all devices to have
    > > resources allocated.
    >
    > There is a nice problem with ISA PNP serial ports generated by this
    > type of thing in 2.5.59.
    >
    > On boot, we probe for the usual serial ports, and discover two at
    > 0x3f8 and 0x2f8, and we request these resources. Please note that
    > one port could be in use as a serial console from earlier in the
    > bootup.
    >
    > Then, we move on to the PNP probes. The PNP layer gives us two
    > serial ports, and we initialise them. The PNP layer notices that
    > the resources for 0x3f8 and 0x2f8, and re-assigns the ports to
    > 0x3e8 and 0x2e8. The serial layer finds two extra ports at
    > 0x3e8 and 0x2e8.
    >
    > However, the ports at 0x3f8 and 0x2f8 are now gone, along with the
    > serial console, and the boot messages claim that we have four serial
    > ports at ttyS0, ttyS1, ttyS2, and ttyS3, when the machine in fact
    > only has two serial ports. The serial layer likewise believes we
    > have four serial ports.
    >
    > I look forward to your thoughts on getting around this problem.

    I think that legacy devices must be probed after PnP ones, otherwise
    you'll get these duplications.

    Jaroslav

    -----
    Jaroslav Kysela <perex@suse.cz>
    Linux Kernel Sound Maintainer
    ALSA Project, SuSE Labs

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