Re: [Xen-devel] [PATCH 09/10] xen: arm: Drop device_tree_node_compatible

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 06/18/2014 03:47 PM, Ian Campbell wrote:
> On Wed, 2014-06-18 at 15:43 +0100, Stefano Stabellini wrote:
>> On Mon, 16 Jun 2014, Ian Campbell wrote:
>>> Instead use fdt_node_check_compatible from libfdt.
>>
>> Unfortunately the two functions are not equivalent:
>> fdt_node_check_compatible uses memcmp while device_tree_node_compatible
>> uses strcasecmp that ignores cases.
> 
> I hadn't spotted this.
> 
> They can't both be spec complaint I think. I expect
> fdt_node_check_compatible (from libfdt) is more likely to be the one
> which is correct.

In dt_device_is_compatible we use strcasecmp as Linux does.

For Linux, it looks like the use a less restrictive way in generic code
(i.e strcasecmp) and more restrictive on SPARC (i.e strcmp)

I can't find anything in the spec to say which one is better. But I
think we want to stay compatible with Linux we have to keep
device_tree_node_compatible and use it in place of
fdt_node_check_compatible.

We could also modify the latter function for our convenience.

Regards.

-- 
Julien Grall

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