Re: [PATCH] drm/panel: simple: fix -Wliteral-conversion warning

From: Thierry Reding
Date: Thu Aug 09 2018 - 06:00:03 EST


On Fri, Jun 15, 2018 at 03:37:49PM -0700, Nick Desaulniers wrote:
> Fixes commit 8cfe83419cdb ("drm/panel: simple: Add
> support for KEO TX31D200VM0BAA")
>
> drivers/gpu/drm/panel/panel-simple.c:1250:27: warning: implicit conversion from
> 'double' to 'u32' (aka 'unsigned int') changes value from 33.5 to 33
> [-Wliteral-conversion]
> .vfront_porch = { 6, 21, 33.5 },
> ~ ^~~~
> drivers/gpu/drm/panel/panel-simple.c:1251:26: warning: implicit conversion from
> 'double' to 'u32' (aka 'unsigned int') changes value from 33.5 to 33
> [-Wliteral-conversion]
> .vback_porch = { 6, 21, 33.5 },
> ~ ^~~~
>
> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> ---
> Alternatively, should these be rounded up to 34? I'm guessing the
> current behaviour (truncation) is correct since that's how the patch was
> operating.

Looks like this is a duplicate of what was merged as:

commit c9b6be7dc13e2f87592ee4c9812cb450dba484d5
Author: Stefan Agner <stefan@xxxxxxxx>
Date: Thu Apr 19 23:20:03 2018 +0200

drm/panel: simple: Fix data type in KEO TX31D200VM0BAA timings

All values in a struct struct timing_entry (every entry in
struct display_timing) require an integer. Choose the closest
safe integer of 32.

This avoids a warning seen with clang:
drivers/gpu/drm/panel/panel-simple.c:1250:27: warning: implicit
conversion from 'double' to 'u32' (aka 'unsigned int')
changes value from 33.5 to 33 [-Wliteral-conversion]
.vfront_porch = { 6, 21, 33.5 },
~ ^~~~
drivers/gpu/drm/panel/panel-simple.c:1251:26: warning: implicit
conversion from 'double' to 'u32' (aka 'unsigned int')
changes value from 33.5 to 33 [-Wliteral-conversion]
.vback_porch = { 6, 21, 33.5 },
~ ^~~~

Signed-off-by: Stefan Agner <stefan@xxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20180419212003.8155-1-stefan@xxxxxxxx

Thierry

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