Re: [Qemu-ppc] [PATCH] sam460ex: Add comment explaining ignored errors from fdt operations

[David Gibson]

On Thu, Jul 05, 2018 at 04:06:28PM +0200, Paolo Bonzini wrote:
> On 05/07/2018 15:51, Guenter Roeck wrote:
> > +        /* Failure to set serial port clocks is not fatal, so just ignore
> > +         * errors when trying to do so.
> > +         */
> > +        (void)fdt_setprop_cell(fdt, offset, "clock-frequency", UART_FREQ);
> >          offset = fdt_node_offset_by_compatible(fdt, offset, "ns16550");
> 
> Ok, but why would it even fail?  Maybe it's not this case, but even if
> it's not fatal for the OS, generating different device trees silently
> seems like a recipe for Heisenbugs.

Yes, quite.  Especially since the most likely errors I can see here
would actually indicate something has already gone horribly wrong with
the device tree construction, so a missing clock-frequency is the
least of our troubles.

I think using _FDT() here would be a better approach.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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