From mboxrd@z Thu Jan 1 00:00:00 1970 From: sergei.shtylyov@cogentembedded.com (Sergei Shtylyov) Date: Thu, 2 Feb 2017 16:02:39 +0300 Subject: [PATCH v2] ARM: dts: r8a7791: link DU to VSPDs In-Reply-To: References: <1529351.Fac5N2tKoF@wasted.cogentembedded.com> <2492577.tBEnW0tCHD@wasted.cogentembedded.com> <4ae454ad-296c-dec9-27e9-fd050333737f@cogentembedded.com> <4bf0b27c-9641-391d-fc05-8cdc20ce4ec3@cogentembedded.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello! On 02/01/2017 03:01 PM, Magnus Damm wrote: >>>>> Add the "vsps" property to the DU device node in order to link this node >>>>> to >>>>> the VSPD nodes. >>>>> >>>>> Signed-off-by: Sergei Shtylyov >>>>> >>>>> --- >>>>> Changes in version 2: >>>>> - rebased the patch. >>>>> >>>>> This patch is against the 'renesas-devel-20170125-v4.10-rc5' of Simon >>>>> Horman's >>>>> 'renesas.git' repo. It's only meaningful if the DRM driver patches >>>>> I've >>>>> just >>>>> posted are applied. >>>> >>>> >>>> >>>> Forgot to note that without this patch the DU driver fails to link to >>>> VSPD and probe correctly, so there's no video signal. So it makes sense >>>> to >>>> apply before the DU driver patch (once it's ACKed for merge)... >>> >>> >>> Doesn't that translate to breaking the DT ABI? Is there someway we can >>> avoid doing that? >> >> >> It doesn't -- if this patch is merged ahead of the DU patches. > > Perhaps I'm misunderstanding, but if you require a DTS patch to be > merged before a driver change then doesn't this mean that older DTBs > will stop working with newer kernels and the user is forced to update > the DTB to avoid breakage? Yes, it seems so. :-( > It would be nice if older DTBs could keep on working as before and the > DU driver modification would work both with connected VSPs and also > keep on working as before in case the VSP connection is not present in > DT. I'll try to look into that... > Cheers, > > / magnus MBR, Sergei