On 14.06.12 at 16:14, Jeff Mahoney
wrote: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 06/14/2012 10:10 AM, Jan Beulich wrote:
On 14.06.12 at 15:37, Jeff Mahoney
wrote: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 06/14/2012 04:53 AM, Olaf Hering wrote:
On Tue, Jun 12, Jan Beulich wrote:
While I questioned whether doing this (for a slim boot time benefit this might provide) is really the right thing already in the past, bug 766284 points out another reason why this is a bad idea. Can this be reverted (in master and 12.2 at least)?
The change below for ata_piix (and other related changes in April 2009) was made without a bugzilla or fate reference. Whats the practical benefit of having the drivers built into the kernel? At least ata_piix should be a module because it also drives emulated hardware (not only in a Xen HVM guest).
The changes came out of the faster booting effort at Intel for Meego (or Moblin, or whatever it was called then), since the initialization can happen in parallel rather than waiting on each module to load in the initrd as happens with a mostly-modular kernel. Greg KH added the changes and presented numbers as to why it was faster at the time.
The fact that ata_piix is also used by emulated hardware is not a reason to make it modular. It's a reason to fix the drivers to work together, or to pull the functionality into the original driver.
If the intended driver is modular, then that driver has no way to tell a built-in one to not control certain devices. So the only option then is to use Olaf's patch (which isn't really desirable imo).
From my perspective, if there are two or more drivers for one piece of hardware (ignore the fact that it's virtual/emulated here), they _all_ should be modular, so that the rest of the system (e.g. modprobe rules) can figure out the right one. The situation really is no different than for other cases where a KMP override is wanted/necessary.
- From my perspective, there shouldn't be more than one driver for a given piece of hardware unless one is planned to phase out the other. That doesn't seem to be the case. The emulated one is a special case of the the canonical one and should be integrated.
Integrated into what? You're aware that we're talking about the PV Hyper-V and Xen drivers, aren't you? Furthermore, there are already multiple drivers for ATA devices - many specialized ones, and ata_generic. I doubt you could force the use of ata_generic on a kernel with built-in ata_piix on devices matched by the latter's MODULE_DEVICE_TABLE() without tedious (almost) manual unbinding (which isn't an option for the problem at hand, since afaict there's no direct correlation between the PV and emulated devices). Jan -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org