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([2a01:e0a:3d9:2080:a24a:bfda:f031:720d]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a06d532ac1sm1244633f8f.72.2025.04.24.01.20.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 24 Apr 2025 01:20:24 -0700 (PDT) Message-ID: Date: Thu, 24 Apr 2025 10:20:23 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Neil Armstrong Reply-To: neil.armstrong@linaro.org Subject: Re: [PATCH] drm: panel: himax-hx8279: avoid using an uninitialized variable To: Arnd Bergmann , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , AngeloGioacchino Del Regno Cc: Arnd Bergmann , Jessica Zhang , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20250423163214.2276114-1-arnd@kernel.org> Content-Language: en-US, fr Autocrypt: addr=neil.armstrong@linaro.org; keydata= xsBNBE1ZBs8BCAD78xVLsXPwV/2qQx2FaO/7mhWL0Qodw8UcQJnkrWmgTFRobtTWxuRx8WWP GTjuhvbleoQ5Cxjr+v+1ARGCH46MxFP5DwauzPekwJUD5QKZlaw/bURTLmS2id5wWi3lqVH4 BVF2WzvGyyeV1o4RTCYDnZ9VLLylJ9bneEaIs/7cjCEbipGGFlfIML3sfqnIvMAxIMZrvcl9 qPV2k+KQ7q+aXavU5W+yLNn7QtXUB530Zlk/d2ETgzQ5FLYYnUDAaRl+8JUTjc0CNOTpCeik 80TZcE6f8M76Xa6yU8VcNko94Ck7iB4vj70q76P/J7kt98hklrr85/3NU3oti3nrIHmHABEB AAHNKk5laWwgQXJtc3Ryb25nIDxuZWlsLmFybXN0cm9uZ0BsaW5hcm8ub3JnPsLAkQQTAQoA OwIbIwULCQgHAwUVCgkICwUWAgMBAAIeAQIXgBYhBInsPQWERiF0UPIoSBaat7Gkz/iuBQJk Q5wSAhkBAAoJEBaat7Gkz/iuyhMIANiD94qDtUTJRfEW6GwXmtKWwl/mvqQtaTtZID2dos04 YqBbshiJbejgVJjy+HODcNUIKBB3PSLaln4ltdsV73SBcwUNdzebfKspAQunCM22Mn6FBIxQ GizsMLcP/0FX4en9NaKGfK6ZdKK6kN1GR9YffMJd2P08EO8mHowmSRe/ExAODhAs9W7XXExw UNCY4pVJyRPpEhv373vvff60bHxc1k/FF9WaPscMt7hlkbFLUs85kHtQAmr8pV5Hy9ezsSRa GzJmiVclkPc2BY592IGBXRDQ38urXeM4nfhhvqA50b/nAEXc6FzqgXqDkEIwR66/Gbp0t3+r yQzpKRyQif3OwE0ETVkGzwEIALyKDN/OGURaHBVzwjgYq+ZtifvekdrSNl8TIDH8g1xicBYp QTbPn6bbSZbdvfeQPNCcD4/EhXZuhQXMcoJsQQQnO4vwVULmPGgtGf8PVc7dxKOeta+qUh6+ SRh3vIcAUFHDT3f/Zdspz+e2E0hPV2hiSvICLk11qO6cyJE13zeNFoeY3ggrKY+IzbFomIZY 4yG6xI99NIPEVE9lNBXBKIlewIyVlkOaYvJWSV+p5gdJXOvScNN1epm5YHmf9aE2ZjnqZGoM Mtsyw18YoX9BqMFInxqYQQ3j/HpVgTSvmo5ea5qQDDUaCsaTf8UeDcwYOtgI8iL4oHcsGtUX oUk33HEAEQEAAcLAXwQYAQIACQUCTVkGzwIbDAAKCRAWmrexpM/4rrXiB/sGbkQ6itMrAIfn M7IbRuiSZS1unlySUVYu3SD6YBYnNi3G5EpbwfBNuT3H8//rVvtOFK4OD8cRYkxXRQmTvqa3 3eDIHu/zr1HMKErm+2SD6PO9umRef8V82o2oaCLvf4WeIssFjwB0b6a12opuRP7yo3E3gTCS KmbUuLv1CtxKQF+fUV1cVaTPMyT25Od+RC1K+iOR0F54oUJvJeq7fUzbn/KdlhA8XPGzwGRy 4zcsPWvwnXgfe5tk680fEKZVwOZKIEuJC3v+/yZpQzDvGYJvbyix0lHnrCzq43WefRHI5XTT QbM0WUIBIcGmq38+OgUsMYu4NzLu7uZFAcmp6h8g Organization: Linaro In-Reply-To: <20250423163214.2276114-1-arnd@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi, On 23/04/2025 18:32, Arnd Bergmann wrote: > From: Arnd Bergmann > > goa_even_valid is only initialized in one branch but not the other: > > drivers/gpu/drm/panel/panel-himax-hx8279.c:838:6: error: variable 'goa_even_valid' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] > 838 | if (num_zero == ARRAY_SIZE(desc->goa_even_timing)) > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/gpu/drm/panel/panel-himax-hx8279.c:842:23: note: uninitialized use occurs here > 842 | if (goa_odd_valid != goa_even_valid) > | ^~~~~~~~~~~~~~ > > Change the initialization to set it to the value of the condition instead. > > Fixes: 38d42c261389 ("drm: panel: Add driver for Himax HX8279 DDIC panels") > Signed-off-by: Arnd Bergmann > --- > drivers/gpu/drm/panel/panel-himax-hx8279.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/panel/panel-himax-hx8279.c b/drivers/gpu/drm/panel/panel-himax-hx8279.c > index b48b350b62da..4f548430654a 100644 > --- a/drivers/gpu/drm/panel/panel-himax-hx8279.c > +++ b/drivers/gpu/drm/panel/panel-himax-hx8279.c > @@ -835,8 +835,7 @@ static int hx8279_check_goa_config(struct hx8279 *hx, struct device *dev) > num_zero++; > } > > - if (num_zero == ARRAY_SIZE(desc->goa_even_timing)) > - goa_even_valid = false; > + goa_even_valid = (num_zero != ARRAY_SIZE(desc->goa_even_timing)); > > /* Programming one without the other would make no sense! */ > if (goa_odd_valid != goa_even_valid) Thanks, Applying https://lore.kernel.org/all/20250423-panel-himax-hx8279-fix-sometimes-uninitialized-v2-1-fc501c6558d9@kernel.org/ instead since more complete. Neil