On Thu, Oct 02, 2014 at 04:08:52PM +0200, Hans de Goede wrote: > > 2) delay the clock/regulator cleanup until after there is a fixed > > window for device specific drivers to load in. Loading from initrd is > > a fixed window. > > As I already explained by example in another mail, this won't work: > > "delaying over the initrd is not helpful. Not having the real driver > load for whatever reasons, is not necessarily a boot blocking event, > and if it us just missing will not lead to any error messages. > > So the boot will continue normally with a black screen, and things are > still impossible to debug." Plus: 1) you might not have an initrd, which doesn't change a thing: your clock get disabled before you can load your driver 2) you might not have a rootfs, and no driver to load, which would leave the clock enabled forever. > We've been down the whole delay till $random point in time thing in the > past with storage enumeration, where you need to wait for say all members > of a raid set to show up. The lesson learned from that is that you should > not wait $random time / event, but wait for the actual storage device to > show up. > > And this is just like that, we need to wait for the actual display driver > to have loaded and taken over before "cleaning up" the clocks used by > the display engine. > > I guess we could just delay all clock cleanup until then, not really > pretty, and I still prefer to just list the clocks in the simplefb > dtnode, but if this version would be acceptable to all involved, I can > live with it. > > Mike, would a patch adding 2 calls like these to the clock core be > acceptable ? : > > clk_block_disable_unused() > clk_unblock_disable_unused() Thierry actually already made such a patch somewhere in this thread. The thing is that it should also block clk_disable (and all the potential users of clk_disable: clk_set_rate, clk_set_parent, etc.) from actually disabling them. Otherwise, you might still end up with your clock disabled. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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