Re: [PATCH] ARM: allow, but warn, when issuing ioremap() on RAM

From: Baruch Siach
Date: Thu Oct 07 2010 - 07:52:35 EST


Hi Felipe,

On Thu, Oct 07, 2010 at 12:44:22PM +0300, Felipe Contreras wrote:
> Many drivers are broken, and there's no alternative in sight. Such a big
> change should stay as a warning for now, and only later should it
> actually fail.
>
> The drivers are not doing something correct, we get it, but for now it's
> better to allow them to work (they do 99% of the time anyway) rather
> than to force everyone to revert this patch in their internal trees
> until there's a solution. A slightly broken functionality is better than
> no functionality at all.
>
> A warning lets people know that what they are doing is not right, and
> they should fix it.

[snip]

> --- a/arch/arm/mm/ioremap.c
> +++ b/arch/arm/mm/ioremap.c
> @@ -204,8 +204,7 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
> /*
> * Don't allow RAM to be mapped - this causes problems with ARMv6+
> */

Please change the comment to match the (new) code.

> - if (WARN_ON(pfn_valid(pfn)))
> - return NULL;
> + WARN_ON(pfn_valid(pfn));
>
> type = get_mem_type(mtype);
> if (!type)

baruch

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