Hi, On Monday, 16 of May 2005 22:16, Adam Belay wrote: > On Fri, May 13, 2005 at 10:06:42PM -0700, Fabrice Gautier wrote: > > Hi, > > > > > From: Shaohua Li [mailto:shaohua.li@xxxxxxxxx] > > > Sent: Wednesday, May 11, 2005 6:25 PM > > > To: linux-pm > > > Subject: [linux-pm] A reference implementation of PCI suspend/resume? > > > > > > Hi, > > > There are still many PCI drivers don't implement their > > > .suspend/.resume > > > methods correctly. I felt it would be quite helpful there is > > > a reference > > > implementation. Here is my thought: > > > > > > [...snip...] > > > > > > Currently many drivers don't call > > > free_irq/request_irq/pci_disable_device, which makes unexpected > > > interrupt occur and even break suspend/resume in some systems. > > > > I don't understand why not calling free_irq would cause unexpected > > interrupts. > > I don't think it would. Please have a look at http://bugzilla.kernel.org/show_bug.cgi?id=4416 Perhaps you can figure out what else is going on there ... > However, there are three reasons in favor of unregister PCI interrupts: > > a.) the kernel will complain if the irq isn't handled, revealing a possible > problem with the driver's suspend routine. > > b.) You're assuming every device has its own interrupt. This may not be the > case. Let's say one device was sharing interrupts with a few other devices. > We don't want it's interrupt handler to mess up things when it tries to read > hardware registers from a physically "off" device, as it may possibly generate > errors. Almost every interrupt handler assumes the device is "on", as it > should. Each interrupt handler has to ask its hardware if it generated the > interrupt. > > c.) Selective device suspending: obviously we don't want to leave stale > interrupt handlers around. I agree. Greets, Rafael -- - Would you tell me, please, which way I ought to go from here? - That depends a good deal on where you want to get to. -- Lewis Carroll "Alice's Adventures in Wonderland"
