On 14/07/2021 15:35, Andy Shevchenko wrote: > On Wed, Jul 14, 2021 at 3:56 PM Ralf Ramsauer > <ralf.ramsauer@xxxxxxxxxxxxxxxxx> wrote: >> On 14/07/2021 08:54, Jiri Slaby wrote: >>> On 13. 07. 21, 12:40, Andy Shevchenko wrote: > >>> Hmm, have you checked the commit which introduced the whitelist? >>> >>> 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. >>> >>> >>> You should have at least CCed the author for an input. >> >> Yep, back then I was testing three different 8250 pci cards. All of them >> claimed to support MSI, while one really worked with MSI, the one that I >> whitelisted. So I thought it would be better to use legacy IRQs as long >> as no one tested a specific card to work with MSI. > > Can you shed a light eventually what those cards are? That's been a while. Let me check that if I can still find them, and I'll test them once again against MSI being enabled. But this can take some days. Ralf > >> Don't do that… And don't convert it to a blacklist. A blacklist will >> break users until they report that something doesn't work. > > White list is not okay either. MSI in general is a right thing to do. > preventing users from MSI is asking for the performance degradation > and IRQ resource conflicts (in case the IRQ line is shared). > > Besides that, shouldn't it be rather the specific field in private (to > 8250_pci) structure than constantly growing list?
