On Tue, Oct 29, 2019 at 09:19:34PM +0000, Marciniszyn, Mike wrote: > > Subject: Re: [PATCH for-rc 1/4] IB/hfi1: Allow for all speeds higher than gen3 > > > > On Fri, Oct 25, 2019 at 03:58:24PM -0400, Dennis Dalessandro wrote: > > > From: James Erwin <james.erwin@xxxxxxxxx> > > > > > > The driver avoids the gen3 speed bump when the parent > > > bus speed isn't identical to gen3, 8.0GT/s. This is not > > > compatible with gen4 and newer speeds. > > > > > > Fix by relaxing the test to explicitly look for the lower > > > capability speeds which inherently allows for all future speeds. > > > > This description does not seem like stable material to me. > > > > Having a card unknowingly operate at half speed would seem pretty serious to me. Since gen4 systems are really new this also sounds like a new feature to me.. You need to be concerned that changing the pci setup doesn't cause regressions on existing systems too. > Perhaps the description should say: > > IB/hfi1: Insure full Gen3 speed in a Gen4 system And maybe explain what the actual user visible impact is here. Sounds like plugging a card into a gen4 system will not run at gen3 speeds? Jason
