linux-kernel - Re: [PATCH] drm/vblank: Fix -Wformat compile warnings on some arches

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Date:   Thu, 21 May 2020 23:09:24 +0200
From:   Sam Ravnborg <sam@...nborg.org>
To:     Lyude Paul <lyude@...hat.com>
Cc:     dri-devel@...ts.freedesktop.org,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>, linux-kernel@...r.kernel.org,
        Dave Airlie <airlied@...hat.com>
Subject: Re: [PATCH] drm/vblank: Fix -Wformat compile warnings on some arches

On Thu, May 21, 2020 at 04:46:47PM -0400, Lyude Paul wrote:
> On some architectures like ppc64le and aarch64, compiling with
> -Wformat=1 will throw the following warnings:
> 
>   In file included from drivers/gpu/drm/drm_vblank.c:33:
>   drivers/gpu/drm/drm_vblank.c: In function 'drm_update_vblank_count':
>   drivers/gpu/drm/drm_vblank.c:273:16: warning: format '%llu' expects
>   argument of type 'long long unsigned int', but argument 4 has type
>   'long int' [-Wformat=]
>     DRM_DEBUG_VBL("updating vblank count on crtc %u:"
>                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   ./include/drm/drm_print.h:407:22: note: in definition of macro
>   'DRM_DEBUG_VBL'
>     drm_dbg(DRM_UT_VBL, fmt, ##__VA_ARGS__)
>                         ^~~
>   drivers/gpu/drm/drm_vblank.c:274:22: note: format string is defined here
>            " current=%llu, diff=%u, hw=%u hw_last=%u\n",
>                      ~~~^
>                      %lu
> 
> So, fix that with a typecast.
> 
> Signed-off-by: Lyude Paul <lyude@...hat.com>
> Co-developed-by: Dave Airlie <airlied@...hat.com>
> ---
>  drivers/gpu/drm/drm_vblank.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> index acb3c3f65b579..1a96db2dd16fa 100644
> --- a/drivers/gpu/drm/drm_vblank.c
> +++ b/drivers/gpu/drm/drm_vblank.c
> @@ -342,7 +342,7 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
>  
>  	DRM_DEBUG_VBL("updating vblank count on crtc %u:"
>  		      " current=%llu, diff=%u, hw=%u hw_last=%u\n",
> -		      pipe, atomic64_read(&vblank->count), diff,
> +		      pipe, (unsigned long long)atomic64_read(&vblank->count), diff,
>  		      cur_vblank, vblank->last);

While touching this you could consider introducing drm_dbg_vbl().
An maybe as a follow-up patch replace all logging in this file with the drm_* variants.

	Sam

>  
>  	if (diff == 0) {
> -- 
> 2.26.2
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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