From 7f4cedd882f7cae83177066c2b239ef457ce4a42 Mon Sep 17 00:00:00 2001 From: Giulio Benetti Date: Fri, 5 Oct 2018 23:59:50 +0200 Subject: [PATCH 1/2] drm/sun4i: tcon: fix check of tcon->panel null pointer Since tcon->panel is a pointer returned by of_drm_find_panel() need to check if it is not NULL, hence a valid pointer. IS_ERR() instead checks return error values, not NULL pointers. Substitute "if (!IS_ERR(tcon->panel))" with "if (tcon->panel)". Signed-off-by: Giulio Benetti Signed-off-by: Maxime Ripard Link: https://patchwork.freedesktop.org/patch/msgid/20181005215951.99003-1-giulio.benetti@micronovasrl.com --- drivers/gpu/drm/sun4i/sun4i_lvds.c | 4 ++-- drivers/gpu/drm/sun4i/sun4i_rgb.c | 4 ++-- drivers/gpu/drm/sun4i/sun4i_tcon.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun4i_lvds.c b/drivers/gpu/drm/sun4i/sun4i_lvds.c index af7dcb6da351..e7eb0d1e17be 100644 --- a/drivers/gpu/drm/sun4i/sun4i_lvds.c +++ b/drivers/gpu/drm/sun4i/sun4i_lvds.c @@ -75,7 +75,7 @@ static void sun4i_lvds_encoder_enable(struct drm_encoder *encoder) DRM_DEBUG_DRIVER("Enabling LVDS output\n"); - if (!IS_ERR(tcon->panel)) { + if (tcon->panel) { drm_panel_prepare(tcon->panel); drm_panel_enable(tcon->panel); } @@ -88,7 +88,7 @@ static void sun4i_lvds_encoder_disable(struct drm_encoder *encoder) DRM_DEBUG_DRIVER("Disabling LVDS output\n"); - if (!IS_ERR(tcon->panel)) { + if (tcon->panel) { drm_panel_disable(tcon->panel); drm_panel_unprepare(tcon->panel); } diff --git a/drivers/gpu/drm/sun4i/sun4i_rgb.c b/drivers/gpu/drm/sun4i/sun4i_rgb.c index bf068da6b12e..f4a22689eb54 100644 --- a/drivers/gpu/drm/sun4i/sun4i_rgb.c +++ b/drivers/gpu/drm/sun4i/sun4i_rgb.c @@ -135,7 +135,7 @@ static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder) DRM_DEBUG_DRIVER("Enabling RGB output\n"); - if (!IS_ERR(tcon->panel)) { + if (tcon->panel) { drm_panel_prepare(tcon->panel); drm_panel_enable(tcon->panel); } @@ -148,7 +148,7 @@ static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder) DRM_DEBUG_DRIVER("Disabling RGB output\n"); - if (!IS_ERR(tcon->panel)) { + if (tcon->panel) { drm_panel_disable(tcon->panel); drm_panel_unprepare(tcon->panel); } diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index c78cd35a1294..e4b3bd0307ef 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -555,7 +555,7 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon, * Following code is a way to avoid quirks all around TCON * and DOTCLOCK drivers. */ - if (!IS_ERR(tcon->panel)) { + if (tcon->panel) { struct drm_panel *panel = tcon->panel; struct drm_connector *connector = panel->connector; struct drm_display_info display_info = connector->display_info; From a8939766c75c06b5a0ab691ecbba9347e4e520cf Mon Sep 17 00:00:00 2001 From: Giulio Benetti Date: Fri, 5 Oct 2018 23:59:51 +0200 Subject: [PATCH 2/2] drm/sun4i: tcon: prevent tcon->panel dereference if NULL If tcon->panel pointer is NULL, trying to dereference from it (i.e. tcon->panel->connector) will cause a null pointer dereference. Add tcon->panel null pointer check before calling sun4i_tcon0_mode_set_dithering(). Signed-off-by: Giulio Benetti Fixes: f11adcecbd5f ("drm/sun4i: tcon: Add dithering support for RGB565/RGB666 LCD panels") Reviewed-by: Chen-Yu Tsai Signed-off-by: Maxime Ripard Link: https://patchwork.freedesktop.org/patch/msgid/20181005215951.99003-2-giulio.benetti@micronovasrl.com --- drivers/gpu/drm/sun4i/sun4i_tcon.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c index e4b3bd0307ef..f949287d926c 100644 --- a/drivers/gpu/drm/sun4i/sun4i_tcon.c +++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c @@ -491,7 +491,8 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon, sun4i_tcon0_mode_set_common(tcon, mode); /* Set dithering if needed */ - sun4i_tcon0_mode_set_dithering(tcon, tcon->panel->connector); + if (tcon->panel) + sun4i_tcon0_mode_set_dithering(tcon, tcon->panel->connector); /* Adjust clock delay */ clk_delay = sun4i_tcon_get_clk_delay(mode, 0);