On Tue, Jan 26, 2021 at 1:27 AM Uwe Kleine-König <uwe@xxxxxxxxxxxxxxxxx> wrote: > > Hello Masahiro, > > On 1/25/21 10:53 PM, Masahiro Yamada wrote: > > On Mon, Jan 25, 2021 at 8:07 PM Uwe Kleine-König <uwe@xxxxxxxxxxxxxxxxx> wrote: > >> > >> Adding the -@ switch to dtc results in the binary devicetrees containing > >> a list of symbolic references and their paths. This is necessary to > >> apply device tree overlays e.g. on Raspberry Pi as described on > >> https://www.raspberrypi.org/documentation/configuration/device-tree.md. > >> > >> Obviously the downside of this change is an increas of the size of the > >> generated dtbs, for an arm out-of-tree build (multi_v7_defconfig): > >> > >> $ du -s arch/arm/boot/dts* > >> 101380 arch/arm/boot/dts-pre > >> 114308 arch/arm/boot/dts-post > >> > >> so this is in average an increase of 12.8% in size. > >> > >> Signed-off-by: Uwe Kleine-König <uwe@xxxxxxxxxxxxxxxxx> > > > > > > (CCing DT ML.) > > makes sense, thanks. > > > https://www.spinics.net/lists/linux-kbuild/msg27904.html > > > > See Rob's comment: > > > > "We've already rejected doing that. Turning on '-@' can grow the dtb > > size by a significant amount which could be problematic for some > > boards." > > The patch was created after some conversation on irc which continued > after I sent the patch. I added the participating parties to Cc:. > > The (relevant) followups were: > > Geert suggested to always generate the symbols and provide a way to > strip the symbols for installation if and when they are not needed. > > Rob said: "I'm less concerned with the size increases, but rather that > labels go from purely source syntax to an ABI. I'd rather see some > decision as to which labels are enabled or not." I've also said move the arm32 dts files to family subdirectories and enable '-@' per directory. I've posted a script to do the whole thing, but I think the preference is one-by-one. This is needed anyways if we're going to start adding overlays which Viresh is working on. Rob
