On Fri, Oct 27, 2017 at 10:33:29PM +0800, icenowy@xxxxxxx wrote: > 在 2017-10-16 20:09，Maxime Ripard 写道： > > On Mon, Oct 16, 2017 at 05:41:10PM +0800, icenowy@xxxxxxx wrote: > > > 在 2017-10-16 17:11，Maxime Ripard 写道： > > > > On Sat, Oct 14, 2017 at 08:29:24PM +0800, Icenowy Zheng wrote: > > > > > A64's Display Engine 2.0 needs a section of SRAM (SRAM C) to be > > > > > claimed. > > > > > > > > Why? > > > > > > Allwinner didn't document this, but if the SRAM is not claimed, the > > > DE2 MMIO zone is totally not accessible. > > > > Not accessible how? It generates an abort when you access it? It > > returns 0? > > > > > It seems that Allwinner uses the SRAM C in the DE2 internally. > > > > Then shouldn't it be tied to all the DE2 devices then? So mixers > > too. Either way, this should be mentionned in your commit logs. How > > you're fixing things is much less interesting than why you're doing > > them. You can tell how you're doing them from your code already. > > Yes I checked and when the SRAM is not claimed any part in DE2 memory > zone can't be accessed. Then all the nodes that depend on it should have it, and the bindings should be modified appropriately. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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