On 04/02/2014 00:36, Sebastian Hesselbarth wrote: > On 02/04/2014 12:16 AM, Willy Tarreau wrote: >> On Thu, Jan 30, 2014 at 11:31:32AM +0100, Sebastian Hesselbarth wrote: >>> On 01/30/14 11:24, Gregory CLEMENT wrote: >>>> On 25/01/2014 19:19, Sebastian Hesselbarth wrote: >>>>> This patch set fixes clk init order that went upside-down with >>>>> v3.14. I haven't really investigated what caused this, but I assume >>>>> it is related with DT node reordering by addresses. >>>> >>>> Can you explain what kind of issue do you observe? >>> >>> Sure. When probing CLK_OF_DECLAREed clock drivers, clock-gating driver >>> gets registered before core-clocks. It therefore cannot resolve it's >>> parent clock name for tclk and all clock gates will have no parent >>> clock. >>> >>> Usually, you'll see in some drivers (e.g. v643xx_eth) div_by_zero errors >>> poping up, when they calculate a frequency division factors based on >>> clock gate frequency, which should have been tclk but is 0 now. >> >> Well, to be honnest, I have no idea whether your patch is the right way >> to fix the problem or not, but what I can say is that it fixes such oopses >> that appear in 3.14-rc1 when booting on mirabox : >> >> Division by zero in kernel. > > Willy, > > you have hit exactly the reason for this patch. > > [...] >> By the way, seeing how often a trick related to the DT is nedeed to solve an >> oops or a panic, I'm really scared that this whole DT mess is just becoming >> the exact copy of the ACPI mess (but 15 years later) and we'll experience the >> same horrible things :-( Sometimes I'm wondering whether there are not too >> many structural things put in there... > > To be precise, it is not a DT-related trick at all. You would have the > same issues, if you'd register those "low-level" (i.e. early) drivers > without DT. It is more about missing init ordering, here. > > There could be different ways to work this out, even elevating clock > devices to "normal" probed devices could be possible. I am sure, in the > long run, it will work out, but now this is a fix for v3.14-rc1. > > @Jason, Andrew, Gregory, Thomas: > Now that v3.14 is out, anything against taking this in as fixes for rc1?
Hi Sebastian, I am not found of this solution I still think it should be done at framework level. However we still have this very annoying issue, and this fix is better than nothing. So I am not against taking this for rc1 with the hope that it will be later revert with a better solution. Thanks, Gregory > > Sebastian > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
