Re: [PATCH] [RESEND] drm/gma500: initialize gma_clock_t structures

From: Arnd Bergmann
Date: Wed Jan 17 2018 - 09:36:35 EST


On Wed, Jan 17, 2018 at 9:27 AM, Daniel Vetter <daniel@xxxxxxxx> wrote:
> On Tue, Jan 16, 2018 at 03:57:10PM +0100, Arnd Bergmann wrote:
>> The two functions pass a partially initialized structure back to the
>> caller after a memset() on the destination.
>>
>> This is not entirely well-defined, most compilers are sensible enough
>> to either keep the zero-initialization for the uninitialized members,
>> but gcc-4.4 does not, and it warns about this:
>>
>> drivers/gpu/drm/gma500/oaktrail_crtc.c: In function 'mrst_sdvo_find_best_pll':
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:175: warning: 'clock.vco' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:175: warning: 'clock.dot' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:175: warning: 'clock.p2' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:175: warning: 'clock.m2' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:175: warning: 'clock.m1' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c: In function 'mrst_lvds_find_best_pll':
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:208: warning: 'clock.p' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:208: warning: 'clock.vco' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:208: warning: 'clock.p2' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:208: warning: 'clock.m2' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:208: warning: 'clock.m1' may be used uninitialized in this function
>> drivers/gpu/drm/gma500/oaktrail_crtc.c:208: warning: 'clock.n' may be used uninitialized in this function
>>
>> This adds an initialization at declaration time to avoid the warning
>> and make it well-defined on all compiler versions.
>>
>> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
>
> Applied to drm-misc-next-fixes for 4.16, thx for your patch.

Thanks!

> Aside: Still don't want commit rights? :-)

I think I'm fine without. While I do tend to have a backlog on DRM
patches that I'd
like to get merged, they are generally of the kind that I should not
apply myself
without the maintainer being involved in some form, and then they can commit
it themselves.

Arnd