linux-kernel - Re: [DT-OVERLAY PATCH] of: overlay: print the offending node name on fixup failure

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Date:   Tue, 25 Feb 2020 12:10:24 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Luca Ceresoli <luca@...aceresoli.net>
Cc:     "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        Frank Rowand <frowand.list@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [DT-OVERLAY PATCH] of: overlay: print the offending node name on
 fixup failure

Hi Luca,

On Tue, Feb 25, 2020 at 11:42 AM Luca Ceresoli <luca@...aceresoli.net> wrote:
> When a DT overlay has a fixup node that is not present in the base DT
> __symbols__, this error is printed:
>
>   OF: resolver: overlay phandle fixup failed: -22
>   create_overlay: Failed to create overlay (err=-22)
>
> which does not help much in finding the node that caused the problem.
>
> Add a debug print with the name of the fixup node that caused the
> error. The new output is:
>
>   OF: resolver: node gpio9 not found in base DT, fixup failed
>   OF: resolver: overlay phandle fixup failed: -22
>   create_overlay: Failed to create overlay (err=-22)
>
> Signed-off-by: Luca Ceresoli <luca@...aceresoli.net>

Thanks for your patch!

Tested-by: Geert Uytterhoeven <geert+renesas@...der.be>

> NOTE: this patch is not for mainline!

Why not?

> It applies on top of the runtime overlay patches at
> git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git on
> branch topic/overlays, currently based on v5.6-rc1. This looked like the
> most up-to-date version of the overlay patches. Should there be a better
> place, please let me know.

Topic/overlays does not contain any changes to drivers/of/resolver.c,
so this patch is applicable to mainline, too.

> --- a/drivers/of/resolver.c
> +++ b/drivers/of/resolver.c
> @@ -321,8 +321,11 @@ int of_resolve_phandles(struct device_node *overlay)
>
>                 err = of_property_read_string(tree_symbols,
>                                 prop->name, &refpath);
> -               if (err)
> +               if (err) {
> +                       pr_err("node %s not found in base DT, fixup failed",
> +                              prop->name);
>                         goto out;
> +               }
>
>                 refnode = of_find_node_by_path(refpath);
>                 if (!refnode) {

Probably you want to print a helpful message here, too?

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds