From: Nathan Chancellor Date: Mon, 8 Sep 2025 20:24:59 +0000 (-0700) Subject: drm/pixpaper: Fix return type of pixpaper_mode_valid() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0265d0ebb409a25d3bb3a19494e0173d06d9d132;p=users%2Fhch%2Fmisc.git drm/pixpaper: Fix return type of pixpaper_mode_valid() When building with -Wincompatible-function-pointer-types-strict, a warning designed to catch kernel control flow integrity (kCFI) issues at build time, there is an instance in the new tiny DRM pixpaper driver: drivers/gpu/drm/tiny/pixpaper.c:982:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_crtc *, const struct drm_display_mode *)' with an expression of type 'int (struct drm_crtc *, const struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] 982 | .mode_valid = pixpaper_mode_valid, | ^~~~~~~~~~~~~~~~~~~ While 'int' and 'enum drm_mode_status' are ABI compatible, hence no regular warning from -Wincompatible-function-pointer-types, the mismatch will trigger a kCFI violation when pixpaper_mode_valid() is called indirectly. Update the return type of pixpaper_mode_valid() to be 'enum drm_mode_status' to clear up the warning and kCFI violation. Fixes: c9e70639f591 ("drm: tiny: Add support for Mayqueen Pixpaper e-ink panel") Signed-off-by: Nathan Chancellor Reviewed-by: Thomas Zimmermann Signed-off-by: Thomas Zimmermann Link: https://lore.kernel.org/r/20250908-drm-pixpaper-fix-mode_valid-return-type-v1-1-705ceaf03757@kernel.org --- diff --git a/drivers/gpu/drm/tiny/pixpaper.c b/drivers/gpu/drm/tiny/pixpaper.c index b1379cb5f030..32598fb2fee7 100644 --- a/drivers/gpu/drm/tiny/pixpaper.c +++ b/drivers/gpu/drm/tiny/pixpaper.c @@ -968,8 +968,8 @@ static const struct drm_crtc_funcs pixpaper_crtc_funcs = { .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state, }; -static int pixpaper_mode_valid(struct drm_crtc *crtc, - const struct drm_display_mode *mode) +static enum drm_mode_status +pixpaper_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode *mode) { if (mode->hdisplay == PIXPAPER_WIDTH && mode->vdisplay == PIXPAPER_HEIGHT) {