On Thu, Jan 19, 2017 at 02:56:42PM +0000, Russell King - ARM Linux wrote: > On Thu, Jan 19, 2017 at 03:46:41PM +0100, Uwe Kleine-König wrote: > > On Thu, Jan 19, 2017 at 12:35:40PM -0200, Fabio Estevam wrote: > > > Hi Uwe, > > > > > > On Thu, Jan 19, 2017 at 12:13 PM, Uwe Kleine-König > > > <u.kleine-koenig@xxxxxxxxxxxxxx> wrote: > > > > > > > Would it be nice to add a comment about why this was added? Something to > > > > prevent a cleanup like "remove empty nodes and invalid memory > > > > configurations". > > > > > > Do you mean something like this? > > > > > > /* "chosen" and "memory" nodes are mandatory */ > > > chosen {}; > > > memory { device_type = "memory"; reg = <0 0>; }; > > > > Not very helpful comment. Something like: > > > > /* > > * The decompressor relies on a pre-existing chosen node to be > > * available to insert the command line and merge other ATAGS > > * info. > > */ > > > > Is it difficult to fix the decompressor? > > ... and that comment would be wrong. Yes, the decompressor relies on it, > as do some uboot versions. Good that we talked about this, otherwise I would have removed that once the decompressor is fixed. So the comment must be /* * The decompressor and also some versions of U-Boot rely on a * pre-existing /chosen node to be available to insert the * command line and merge other ATAGS info. * Also for U-Boot there must be a pre-existing /memory node. */ > > I didn't understood the breakage regarding the memory node good enough > > to suggest a comment for that. > > A missing memory node appears to prevent some uboot versions supplying > any kind of memory layout to the kernel, which then causes the kernel to > crash very early during boot. > > Again, this is not using appended DTB - this is using a separately loaded > DTB in uboot. uboot fails to update the dtb if these nodes are missing. > > Frankly, I think the original change (removing the skeleton.dtsi include) > was misguided and needs to be reverted - the change is imho built upon an > incorrect assumption that nothing in skeleton.dtsi is required. That's > clearly false. I tend to agree as I assume it's not only U-Boot on i.MX but on all ARM platforms. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html