On Tue, 26 Apr 2005, Grant Grundler wrote: > > I looked into the possibility of having the PCI core disable interrupt > > generation and DMA on each new device as it is discovered. Unfortunately > > there is no dependable, universal way to do this for IRQs. > > Sure there is. Every IRQ line goes to an IRQ controller. > Arch specific code deals with programming the controller and can > mask all interrupts (or not). Historically, they've been left unmasked > for ISA IRQ discovery and debugging misrouted IRQ lines.
This doesn't help. Consider what happens when two devices share an IRQ line. Suppose device B is generating interrupt requests when the driver for device A is probed. The driver registers its handler, which causes the IRQ line to be unmasked. Then a multitude of IRQs arrive from B, none of which can be handled by A's driver. So the kernel shuts the IRQ line down permanently... Alan Stern ------------------------------------------------------- SF.Net email is sponsored by: Tell us your software development plans! Take this survey and enter to win a one-year sub to SourceForge.net Plus IDC's 2005 look-ahead and a copy of this survey Click here to start! http://www.idcswdc.com/cgi-bin/survey?id=105hix _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
