Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Arnd Bergmann]

On Thu, Feb 25, 2021 at 10:34 PM 'Nick Desaulniers' via Clang Built
Linux <clang-built-linux@xxxxxxxxxxxxxxxx> wrote:
> return parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, vsdb_info) ? i : -ENODEV;
>
> would suffice, but the patch is still fine as is.

Right, I did not want to change more than necessary here, and the
original code already had the extra assignment instead of returning
the value.

> > @@ -9857,8 +9857,8 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector,
> >                         }
> >                 }
> >         } else if (edid && amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A) {
> > -               hdmi_valid_vsdb_found = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);
> > -               if (hdmi_valid_vsdb_found && vsdb_info.freesync_supported) {
> > +               i = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);
> > +               if (i >= 0 && vsdb_info.freesync_supported) {
>
> reusing `i` here is safe, for now, but reuse of variables like this in
> separate branches like this might not get noticed if the function is
> amended in the future.
>
> >                         timing  = &edid->detailed_timings[i];
> >                         data    = &timing->data.other_data;

The entire point of the patch is that 'i' is in fact used in the following line,
but was lacking an intialization.

       Arnd