On Sat, May 02, 2009 at 09:55:01AM +0200, Christoph Egger wrote: > Quentin Garnier wrote: > > On Sat, May 02, 2009 at 12:56:43AM +0200, Christoph Egger wrote: > >> Drivers attaches in the device tree independent if their attachment > >> function failed or not. The autoconf framework isn't aware of this, > >> because the attachment function doesn't return an error code. > >> > >> dyoung@ started to work on the drivers to detach the drivers > >> on shutdown/reboot. The drivers' detach function doesn't know if > >> the attachment failed or not. It only can carefully > >> check which resource was allocated and which not and free the > >> allocated ones. > > > > No matter what happens, one has to be careful not to free resources it > > didn't alloc. I don't see how anything could change that. > > > >> Attached patch modifies the driver's attachment function to > >> return an error code, zero for success. > > > > While I understand where this comes from, autoconf(9) has more short- > > comings than just that one, and fixing them will require touching every > > single driver in the tree, too. I'd rather see that done just once. > > Can you enlist all shortcomings, please ? In a nutshell, autoconf(9) doesn't allow a device to exist without a driver attached to it. That's why there is an on-going effort to split the struct device from a driver's softc. It is a necessary step to more radical changes to the autoconf(9) API. [...] > > You can't move the attach callbacks around the call to > > device_register(). (I'll grant you that it is #if 0'd in the pseudo- > > device case, but it might not stay that way eventually.) > > > > device_register() has to happen before the attach callback because the > > system will typically set properties for the attach callback to use > > during that call. I don't know how device_register() users could > > react if the device they've just messed with disappear immediately. It > > has to be checked carefully. > > On x86, device_register() is used to set bootdev. When prompted for > the boot device, the failed devices shouldn't be listed. Is this why you did such a change? > When other platforms do other things that need to be undone, then > we need a device_deregister() for autoconf's error path. And the detach path too. -- Quentin Garnier - cube%cubidou.net@localhost - cube%NetBSD.org@localhost "See the look on my face from staying too long in one place [...] every time the morning breaks I know I'm closer to falling" KT Tunstall, Saving My Face, Drastic Fantastic, 2007.
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