Re: [PATCH 2/2] drm/i915: Add Backlight Control using DPCD for eDP connectors (v5)

Daniel Stone
2016-01-12T17:27:47Z

On 12 January 2016 at 17:18, Jani Nikula <jani.nikula@intel.com> wrote:
> On Tue, 12 Jan 2016, Daniel Stone <daniel@fooishbar.org> wrote:
>> On 12 January 2016 at 15:59, Yetunde Adebisi <yetundex.adebisi@intel.com> wrote:
>>> + memset(intel_dp->edp_dpcd, 0, sizeof(intel_dp->edp_dpcd));
>>
>> gcc should've warned you about this; you're memsetting too small a size.
>
> Really? I think it's fine.

foo.c:11:23: warning: argument to ‘sizeof’ in ‘memset’ call is the
same expression as the destination; did you mean to dereference it?
[-Wsizeof-pointer-memaccess]
memset(bar, 0, sizeof(bar));
^

Either it should be memset(&intel_dp->edp_dpcd, ...), or it should be
sizeof(*intel_dp->edp_dpcd). Unless the intention is genuinely just to
clear the size of one pointer and not the entire structure, in which
case this is terribly misleading.

Cheers,
Daniel