Re: [PATCH v2] drm/pl111: Use 64-bit arithmetic instead of 32-bit

From: Eric Anholt
Date: Tue Jul 17 2018 - 14:40:13 EST


"Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx> writes:

> Add suffix ULL to constant 1000 in order to give the compiler complete
> information about the proper arithmetic to use.
>
> Notice that such constant is used in a context that expects an
> expression of type u64 (64 bits, unsigned) and the following
> expression is currently being evaluated using 32-bit arithmetic:
>
> mode->clock * 1000
>
> Addresses-Coverity-ID: 1466139 ("Unintentional integer overflow")
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

This is silly. The clock won't be over 4ghz -- we haven't seen anything
over 1024x768 on this hardware as far as I know. The u64 is for the
multiplication by width/height below.

I've still applied the patch to shut up the tool.

Attachment: signature.asc
Description: PGP signature