Messages in this thread | | | Date | Sat, 27 Sep 2008 22:53:57 +0200 | From | Ingo Molnar <> | Subject | Re: [Bug #11550] pnp: Huge number of "io resource overlap" messages |
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* Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
> The problem seems to be that Frans has some PCI devices that are not > configured by the BIOS, and their BARs contain zero. A PNP quirk > checks for overlaps of PCI devices and PNP devices, and those zero- > valued BARs of course conflict with the PNP motherboard devices that > describe legacy hardware. > > Here's another approach based on section 3.5 of the PCI Firmware spec. > It says: > > Since not all devices may be configured prior to the operating > system handoff, the operating system needs to know whether a > specific BAR register has been configured by firmware. The operating > system makes the determination by checking the I/O Enable, and > Memory Enable bits in the device's command register, and Expansion > ROM BAR enable bits. If the enable bit is set, then the corresponding > resource register has been configured. > > So instead of checking whether the BAR contains zero, the patch below > checks the I/O, Mem, and ROM BAR enable bits to determine whether a > BAR is enabled.
cool! Looks like a pretty significant fix, for all sorts of legacy devices. Worth backporting?
Ingo
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