linux-kernel - [lst:imx8mp-hdmi 5/11] drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c:76:11: warning: variable 'bus_flags' is used uninitialized whenever 'if' condition is false

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Message-ID: <202208281910.qUZY1Xem-lkp@intel.com>
Date:   Sun, 28 Aug 2022 19:51:11 +0800
From:   kernel test robot <lkp@...el.com>
To:     Lucas Stach <l.stach@...gutronix.de>
Cc:     llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
        linux-kernel@...r.kernel.org
Subject: [lst:imx8mp-hdmi 5/11]
 drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c:76:11: warning: variable
 'bus_flags' is used uninitialized whenever 'if' condition is false

tree:   https://git.pengutronix.de/git/lst/linux imx8mp-hdmi
head:   7e80a6e2d0a4709e471ab951a64d323534a6776f
commit: b3d9e9dfedb64ed82e797a87259e6f7598f5b4d5 [5/11] drm/imx: add driver for HDMI TX Parallel Video Interface
config: riscv-randconfig-c006-20220828 (https://download.01.org/0day-ci/archive/20220828/202208281910.qUZY1Xem-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project a2100daf12fb980a29fd1a9c85ccf8eaaaf79730)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv-linux-gnu
        git remote add lst https://git.pengutronix.de/git/lst/linux
        git fetch --no-tags lst imx8mp-hdmi
        git checkout b3d9e9dfedb64ed82e797a87259e6f7598f5b4d5
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/gpu/drm/bridge/imx/ drivers/gpu/drm/rcar-du/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@...el.com>

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c:76:11: warning: variable 'bus_flags' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           else if (bridge_state)
                    ^~~~~~~~~~~~
   drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c:79:6: note: uninitialized use occurs here
           if (bus_flags & DRM_BUS_FLAG_DE_HIGH)
               ^~~~~~~~~
   drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c:76:7: note: remove the 'if' if its condition is always true
           else if (bridge_state)
                ^~~~~~~~~~~~~~~~~
   drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c:55:15: note: initialize the variable 'bus_flags' to silence this warning
           u32 bus_flags, val;
                        ^
                         = 0
   1 warning generated.


vim +76 drivers/gpu/drm/bridge/imx/imx8mp-hdmi-pvi.c

    45	
    46	static void imx_hdmi_pvi_bridge_enable(struct drm_bridge *bridge,
    47					       struct drm_bridge_state *bridge_state)
    48	{
    49		struct drm_atomic_state *state = bridge_state->base.state;
    50		struct imx_hdmi_pvi *pvi = to_imx_hdmi_pvi(bridge);
    51		struct drm_connector_state *conn_state;
    52		const struct drm_display_mode *mode;
    53		struct drm_crtc_state *crtc_state;
    54		struct drm_connector *connector;
    55		u32 bus_flags, val;
    56	
    57		connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
    58		conn_state = drm_atomic_get_new_connector_state(state, connector);
    59		crtc_state = drm_atomic_get_new_crtc_state(state, conn_state->crtc);
    60	
    61		if (WARN_ON(pm_runtime_resume_and_get(pvi->dev)))
    62			return;
    63	
    64		mode = &crtc_state->adjusted_mode;
    65	
    66		val = PVI_CTL_INPUT_LCDIF;
    67	
    68		if (mode->flags & DRM_MODE_FLAG_PVSYNC)
    69			val |= PVI_CTL_OP_VSYNC_POL | PVI_CTL_INP_VSYNC_POL;
    70	
    71		if (mode->flags & DRM_MODE_FLAG_PHSYNC)
    72			val |= PVI_CTL_OP_HSYNC_POL | PVI_CTL_INP_HSYNC_POL;
    73	
    74		if (pvi->next_bridge->timings)
    75			bus_flags = pvi->next_bridge->timings->input_bus_flags;
  > 76		else if (bridge_state)
    77			bus_flags = bridge_state->input_bus_cfg.flags;
    78	
    79		if (bus_flags & DRM_BUS_FLAG_DE_HIGH)
    80			val |= PVI_CTL_OP_DE_POL | PVI_CTL_INP_DE_POL;
    81	
    82		writel(val, pvi->regs + HTX_PVI_CTL);
    83		val |= PVI_CTL_EN;
    84		writel(val, pvi->regs + HTX_PVI_CTL);
    85	}
    86	

-- 
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https://01.org/lkp