On Wed, Mar 14, 2018 at 7:49 PM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > On Wed, Mar 14, 2018 at 06:31:38PM +0200, Andy Shevchenko wrote: >> On Tue, Mar 13, 2018 at 11:45 PM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: >> > If a device already has MSI or MSI-X enabled, there's no need to set up its >> > legacy INTx interrupt. >> >> Just point to the actual behaviour of this. > > By "point to the actual behaviour", do you mean adding something to > the changelog along the lines of the following? > > If MSI or MSI-X is enabled, the device uses that. It uses INTx only > if both MSI and MSI-X are disabled (see PCIe r4.0, sec 7.7.1.2). > > I did add that because I think that spec reference is useful. If you > have something else in mind, maybe an example would help me > understand. I meant that the behaviour now is changed from check MSI only case to check MSI _or MSI-x_ case Not all code paths may survive that. >> In some cases code in question has to distinguish between MSI and >> MSI-x. So, this or similar changes has to be done with keeping >> above in mind. >> >> (Existing example is Thunderbolt driver) > > Sorry, I didn't get your point here. Certainly some code needs to > distinguish between MSI and MSI-X, but I don't think that's the case > here. I'm not proposing to change Thunderbolt; I do see that it uses > dev->msix_enabled (but not dev->msi_enabled), and it doesn't look like > using pci_dev_msi_enabled() there would be appropriate. Exactly, that's why I pointed on above. -- With Best Regards, Andy Shevchenko
