linux-kernel - Re: [PATCH 1/1] drm/amd/powerplay: initialize a variable before using it

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Message-ID: <CADnq5_NxDMRiO7ct1w53q=0CyqwnRoe+fOS66X+BM1vrmjSZ3g@mail.gmail.com>
Date:   Mon, 6 Nov 2017 16:48:07 -0500
From:   Alex Deucher <alexdeucher@...il.com>
To:     Nicolas Iooss <nicolas.iooss_linux@....org>
Cc:     Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        David Airlie <airlied@...ux.ie>,
        ML dri-devel <dri-devel@...ts.freedesktop.org>,
        amd-gfx list <amd-gfx@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] drm/amd/powerplay: initialize a variable before using it

On Sat, Nov 4, 2017 at 8:21 AM, Nicolas Iooss
<nicolas.iooss_linux@....org> wrote:
> On Sun, Sep 3, 2017 at 2:00 PM, Nicolas Iooss
> <nicolas.iooss_linux@....org> wrote:
>>
>> Function vega10_apply_state_adjust_rules() only initializes
>> stable_pstate_sclk_dpm_percentage when
>> data->registry_data.stable_pstate_sclk_dpm_percentage is not between 1
>> and 100. The variable is then used to compute stable_pstate_sclk, which
>> therefore uses an uninitialized value.
>>
>> Fix this by initializing stable_pstate_sclk_dpm_percentage to
>> data->registry_data.stable_pstate_sclk_dpm_percentage.
>>
>> This issue has been found while building the kernel with clang. The
>> compiler reported a -Wsometimes-uninitialized warning.
>>
>> Fixes: f83a9991648b ("drm/amd/powerplay: add Vega10 powerplay support (v5)")
>> Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@....org>
>> ---
>>  drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
>> index 197174e562d2..c8d28f78cd47 100644
>> --- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
>> +++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c
>> @@ -3043,6 +3043,8 @@ static int vega10_apply_state_adjust_rules(struct pp_hwmgr *hwmgr,
>>
>>         if (phm_cap_enabled(hwmgr->platform_descriptor.platformCaps,
>>                         PHM_PlatformCaps_StablePState)) {
>> +               stable_pstate_sclk_dpm_percentage =
>> +                       data->registry_data.stable_pstate_sclk_dpm_percentage;
>>                 PP_ASSERT_WITH_CODE(
>>                         data->registry_data.stable_pstate_sclk_dpm_percentage >= 1 &&
>>                         data->registry_data.stable_pstate_sclk_dpm_percentage <= 100,
>> --
>> 2.14.1
>
> Hello,
> I have not received any comment on the above patch that I sent two
> months ago, and the issue which is fixed by it still exists in today's
> linux-next code [1]. Could you please review this patch?

Reviewed and applied.  Sorry for missing this.  Feel free to ping
sooner if it looks like something slipped through the cracks.

Thanks,

Alex

>
> Thanks,
> Nicolas
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/gpu/drm/amd/powerplay/hwmgr/vega10_hwmgr.c#n3137
> _______________________________________________
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> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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