On Fri, Sep 19, 2008 at 11:18:11AM -0600, Matthew Wilcox wrote: > On Fri, Sep 19, 2008 at 10:10:20AM -0700, Roland Dreier wrote: > > Yesterday at the Plumbers Conference we talked briefly about removing > > the PCI_MSI Kconfig option (and just always building MSI support). > > Coincidentally, I just had a colleague ask me for help because MSI > > wasn't working on a Fedora 9 system. I investigated a little and > > discovered that current Fedora kernels are built with CONFIG_PCI_MSI=y > > but have an extra patch added that defaults MSI to off (and requires > > booting with "pci=msi" to enable MSI). > > I would query your use of the term 'briefly' -- I think we spent about > twenty minutes on this aspect of MSI ;-) > > > So it seems one way forward would be to get rid of CONFIG_PCI_MSI and > > always build MSI support, but add something like CONFIG_PCI_MSI_DEFAULT > > that allows someone to configure whether to default to allowing MSI (but > > with the "pci=nomsi" boot option possible), or to default to the Fedora > > case (no MSI used unless booted with "pci=msi"). > > What I thought we agreed on last night was: > > - Add support to the PCI core to let drivers report "I didn't get an > MSI, suspect this machine to be broken" (patches already floating around, > need one last push to get them merged). > - Add support to storage drivers to use that facility, in particular > AHCI. > - Turn this on by default in Fedora, wait for kerneloops to pick up > all the PCI hierarchy traces > - Update the blacklists in the kernel > - Remove the PCI_MSI config option > - Remove the per-driver 'nomsi' options That makes sense as long as someone is willing to pick up the pieces and update the blacklists. Last time I tried to just "always enable" MSI, _LOTS_ of hardware broke, so we can't just unconditionally turn it on at this point in time :( thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
