Am Montag, 9. April 2018, 17:53:01 CEST schrieb Robin Murphy: > On 09/04/18 16:44, Heiko Stübner wrote: > > Hi Tomeu, > > > > Am Montag, 9. April 2018, 16:41:56 CEST schrieb Tomeu Vizoso: > >> in today's linux-next, the DRM driver fails to probe because the iommu > >> driver fails to find the aclk. I need to apply this patch for things > >> to work again. > > > > Thanks for catching that issue. > > > > This seems to expose a backwards-compatibility issue, as this breaks > > all old devicetrees, so should get a proper fix, apart from me applying > > the dt-patch I missed. > > > > Looking at the iommu-clock-handling patch, I imagine this part as > > the culprit: > > > > + iommu->num_clocks = ARRAY_SIZE(rk_iommu_clocks); > > + iommu->clocks = devm_kcalloc(iommu->dev, iommu->num_clocks, > > + sizeof(*iommu->clocks), GFP_KERNEL); > > + if (!iommu->clocks) > > + return -ENOMEM; > > > > The clk-bulk functions seem to work with simple for loops and > > should (as the other standard clock functions) just work fine with > > an empty struct, so I guess a simple > > > > if (!iommu->clocks && iommu->num_clocks > 0) > > > > return -ENOMEM; > > > > should hopefully be enough. I'll try to give this a test later on > > if nobody beats me to it :-) > > But iommu->num_clocks is clearly set to a nonzero compile-time constant > at this point ;) > > I'd assume it's the return from devm_clk_bulk_get() which needs to > special-case the "no clocks found" case from any other error, and *then* > blat num_clocks to 0 if so.
you're right of course. Looking at it again, I now clearly see the ARRAY_SIZE and am wondering what made me think num_clocks would be runtime-read. Must be those 25°C today ;-)