On Sun, Jul 15, 2012 at 05:19:21PM -0700, Greg KH wrote: > On Sun, Jul 15, 2012 at 04:55:48PM -0700, Jon Mason wrote: > > On Sat, Jul 14, 2012 at 10:10:15AM -0700, Greg KH wrote: > > > On Fri, Jul 13, 2012 at 02:44:59PM -0700, Jon Mason wrote: > > > > +static int max_num_cbs = 2; > > > > +module_param(max_num_cbs, uint, 0644); > > > > +MODULE_PARM_DESC(max_num_cbs, "Maximum number of NTB transport connections"); > > > > + > > > > +static bool no_msix; > > > > +module_param(no_msix, bool, 0644); > > > > +MODULE_PARM_DESC(no_msix, "Do not allow MSI-X interrupts to be selected"); > > > > > > How would a user, or a distro, know to set these options? Why are they > > > even options at all? > > > > Good question. There is actually a potential benefit to disabling > > MSI-X. The NTB device on one of our platforms only has 3 MSI-X > > vectors. In the current driver design, that would limit them to 3 > > client/virtual devices. However, there are 15bits in the ISR that can > > be used for the same purpose. So, if you disable MSI-X, you can have > > 15 instead of 3. > > But again, how would a user, or a distro, know to set these? Where is > the documentation describing it? Why really have these options at all > and not just fix the platform issues (only 3 MSI-X vectors? Really?) I believe we'll want multiple clients (or have multiqueue Ethernet). I'm happy to add something to /Documentation to describe it and why it would be useful, or I can remove it and re-introduce it when I add multiqueue Ethernet. 3 MSI-X vectors (plus one for PCI-E link up/down) on Xeon NTB, and 33 for Atom NTB. Yeah, really. > > 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
