On Fri, Mar 26, 2021 at 11:42:46PM +0200, Andy Shevchenko wrote: > On Fri, Mar 26, 2021 at 04:26:55PM -0500, Bjorn Helgaas wrote: > > [+cc Randy, Andrew (though I'm sure you have zero interest in this > > ancient question :))] > > > > On Wed, Dec 09, 2020 at 09:31:21AM +0100, Heiner Kallweit wrote: > > > pci_set_mwi() and pci_try_set_mwi() do exactly the same, just that the > > > former one is declared as __must_check. However also some callers of > > > pci_set_mwi() have a comment that it's an optional feature. I don't > > > think there's much sense in this separation and the use of > > > __must_check. Therefore remove pci_try_set_mwi() and remove the > > > __must_check attribute from pci_set_mwi(). > > > I don't expect either function to be used in new code anyway. > > > > There's not much I like better than removing things. But some > > significant thought went into adding pci_try_set_mwi() in the first > > place, so I need a little more convincing about why it's safe to > > remove it. > > > > The argument should cite the discussion about adding it. I think one > > of the earliest conversations is here: > > https://lore.kernel.org/linux-ide/20070404213704.224128ec.randy.dunlap@xxxxxxxxxx/ > > It's solely PCI feature which is absent on PCIe. > > So, if there is a guarantee that the driver never services a device connected > to old PCI bus, it's okay to remove the call (it's no-op on PCIe anyway). Yes, I'm aware that MWI is a no-op on PCIe. If we want to argue that we don't need to support Conventional PCI devices, that should be explicit, and we could remove pci_set_mwi() completely. But I don't think we're ready to drop Conventional PCI support. > OTOH, PCI core may try MWI itself for every device (but this is an opposite, > what should we do on broken devices that do change their state based on that > bit while violating specification). > > In any case > > Acked-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Thanks! Bjorn
