On Wed, Jul 14, 2021 at 9:55 AM Jiri Slaby <jirislaby@xxxxxxxxxx> wrote: > > On 13. 07. 21, 12:40, Andy Shevchenko wrote: > > There is no need to try MSI/MSI-X only on selected devices. > > If MSI is not supported while neing advertised it means device > > being > > > is broken and we rather introduce a list of such devices which > > hopefully will be small or never appear. > > Hmm, have you checked the commit which introduced the whitelist? Nope, my bad. > Nevertheless, this needs to handled with care: while many 8250 devices > actually claim to support MSI(-X) interrupts it should not be > enabled be > default. I had at least one device in my hands with broken MSI > implementation. > > So better introduce a whitelist with devices that are known to support > MSI(-X) interrupts. I tested all devices mentioned in the patch. Thanks, but I still think that blacklisting is better. All drivers I have split (or participated in splitting) from 8250_pci have enabled MSI for the entire subset they serve for. > You should have at least CCed the author for an input. Thanks. I also added Randy, who extended the list. ... > > + pci_set_master(dev); > > But bus mastering is not about MSIs. Strictly speaking it's not, but MSI won't work without DMA. > I *think* it's still OK, but you > need to document that in the commit log too. > > Actually, why the commit which added this code turns on bus mastering? -- With Best Regards, Andy Shevchenko
