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[91.67.64.131]) by smtp.gmail.com with ESMTPSA id q3sm1492343wmc.25.2021.09.22.10.31.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Sep 2021 10:31:47 -0700 (PDT) Subject: Re: [PATCH][next] drm/rockchip: Remove redundant assignment of pointer connector To: =?UTF-8?Q?Heiko_St=c3=bcbner?= , Colin King , Sandy Huang , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210922112416.182134-1-colin.king@canonical.com> <27c79f7a-8e4c-fad8-c6cf-a89793f2e3c6@gmail.com> <22365175.EbdSka62eY@diego> From: Alex Bee Message-ID: <6d18a1a6-37e3-41f9-ddd1-1dae33864d23@gmail.com> Date: Wed, 22 Sep 2021 19:31:46 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <22365175.EbdSka62eY@diego> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: kernel-janitors@vger.kernel.org Hi Heiko, Am 22.09.21 um 18:45 schrieb Heiko Stübner: > Hi Alex, > > Am Mittwoch, 22. September 2021, 18:35:38 CEST schrieb Alex Bee: >> Hi Colin, >> Am 22.09.21 um 13:24 schrieb Colin King: >>> From: Colin Ian King >>> >>> The pointer connector is being assigned a value that is never >>> read, it is being updated immediately afterwards. The assignment >>> is redundant and can be removed. >> The pointer to the connector is used in rockchip_rgb_fini for >> drm_connector_cleanup. >> It's pretty much the same for the encoder, btw. > I think the issue is more the two lines > > connector = &rgb->connector; > connector = drm_bridge_connector_init(rgb->drm_dev, encoder); > > hence the connector = &rgb->connector being overwritten immediately after > > Now that I look at it again, the whole approach looks strange. > drm_bridge_connector_init() creates the connector structure and > returns a pointer to it. Totally agreed. The main reason I was doing it that way, was the way it was done already in rockchip_lvds.c, where the connector was already existent in the struct rockchip_lvds (and was already used in the panel-case - all places where it is used accept pointers also, btw) and is *no* pointer - and is done already this very strange way. I wanted to re-use it for the bridge-case and didn't want to differ in coding in rockchip-rgb to much. The only reason I can think of, why it was done that way is, that we might need a pointer to a fully initialized struct drm_connector for some reason (drm_connector_cleanup ?), what we wouldn't have if have just a pointer and something goes wrong before drm_connector_init respectivly drm_bridge_connector_init. Alex > So the first line below sets the connector pointer to point to the > &rgb->connector element and the second line then set a completely > different address into it. > > So the connector element in rockchip_lvds and rockchip_rgb should actually > become a pointer itself to hold the connector element returned from > drm_bridge_connector_init() . > > > Heiko > >> Regards, >> >> Alex >>> Addresses-Coverity: ("Unused value") >>> Signed-off-by: Colin Ian King >>> --- >>> drivers/gpu/drm/rockchip/rockchip_rgb.c | 1 - >>> 1 file changed, 1 deletion(-) >>> >>> diff --git a/drivers/gpu/drm/rockchip/rockchip_rgb.c b/drivers/gpu/drm/rockchip/rockchip_rgb.c >>> index 09be9678f2bd..18fb84068a64 100644 >>> --- a/drivers/gpu/drm/rockchip/rockchip_rgb.c >>> +++ b/drivers/gpu/drm/rockchip/rockchip_rgb.c >>> @@ -150,7 +150,6 @@ struct rockchip_rgb *rockchip_rgb_init(struct device *dev, >>> if (ret) >>> goto err_free_encoder; >>> >>> - connector = &rgb->connector; >>> connector = drm_bridge_connector_init(rgb->drm_dev, encoder); >>> if (IS_ERR(connector)) { >>> DRM_DEV_ERROR(drm_dev->dev, >>> >> > > >