On Wed, Dec 05, 2018 at 12:48:47PM +0100, Linus Walleij wrote: > On Wed, Dec 5, 2018 at 12:36 PM Charles Keepax > <ckeepax@xxxxxxxxxxxxxxxxxxxxx> wrote: > > On Sun, Dec 02, 2018 at 11:23:07PM -0500, Paul Gortmaker wrote: > > > The solution to #4 is similar - we delete the ".remove" function and > > > the binding into the platform_driver struct. However, since the same > > > ".remove" function could also be triggered by an "unbind" (such as for > > > pass-through of a device to a guest instance) - so we also explicitly > > > disable any unbind for the driver. > > > > > > The unbind mask allows us to ensure we will see if there was some odd > > > corner case out there that was relying on it. Typically it would be a > > > multi-port ethernet card passing a port through to a guest, so a > > > sensible use case in MFD drivers seems highly unlikely. This same > > > solution has already been used in multiple other mainline subsystems. > > > > > > > I guess if this is a general direction thing, but it does seem > > that module unload is not the only reason one might ever unbind a > > driver. So are we sure we want to remove the option to unbind > > these drivers? Certainly for testing it is sometimes useful. > > I personally never understood why these attributes are even > present on non-modular drivers. > > If testing is about exercising unbind/bind to reintialize > the code through a new call to .probe(), why would the developer > not take it all the way through and make it a module? > It just looks like a half-measure. > Well I guess in someways it is a half-measure. I vaguely seem to remember some dependency nightmare that can make it really hard to have the MFD allowed as a module in some cases, I can't remember the exact details but probably why some of these are not modules. I certainly don't strongly object to removing the ability to unbind these drivers, just wanted to make sure everyone is aligned that it's a good thing to do. Does kinda remove a couple of debugging options (debugging things like drivers interfering with each other) and the last chance restart the driver and see if that helps rescue something. Thanks, Charles
