From 333d2da5b7cf8046aee88c0412170be5f6f1ed55 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Tue, 18 Oct 2016 01:41:12 +0300 Subject: drm: WARN when calling drm_format_info() for an unsupported format The format helpers have historically treated unsupported formats as part of the default case, returning values that are likely wrong. We can't change this behaviour now without risking breaking drivers in difficult to detect ways, but we can WARN on unsupported formats to catch faulty callers. The only exception is the framebuffer_check() function that calls drm_format_info() to validate the format passed from userspace. This is a valid use case that shouldn't generate a warning. Signed-off-by: Laurent Pinchart Reviewed-by: Tomi Valkeinen Signed-off-by: Archit Taneja Link: http://patchwork.freedesktop.org/patch/msgid/1476744081-24485-5-git-send-email-laurent.pinchart@ideasonboard.com --- drivers/gpu/drm/drm_fourcc.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) (limited to 'drivers/gpu/drm/drm_fourcc.c') diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c index 23d4b82ec17c..523ed916a1c0 100644 --- a/drivers/gpu/drm/drm_fourcc.c +++ b/drivers/gpu/drm/drm_fourcc.c @@ -102,15 +102,11 @@ char *drm_get_format_name(uint32_t format) } EXPORT_SYMBOL(drm_get_format_name); -/** - * drm_format_info - query information for a given format - * @format: pixel format (DRM_FORMAT_*) - * - * Returns: - * The instance of struct drm_format_info that describes the pixel format, or - * NULL if the format is unsupported. +/* + * Internal function to query information for a given format. See + * drm_format_info() for the public API. */ -const struct drm_format_info *drm_format_info(u32 format) +const struct drm_format_info *__drm_format_info(u32 format) { static const struct drm_format_info formats[] = { { .format = DRM_FORMAT_C8, .depth = 8, .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1 }, @@ -184,6 +180,26 @@ const struct drm_format_info *drm_format_info(u32 format) return NULL; } + +/** + * drm_format_info - query information for a given format + * @format: pixel format (DRM_FORMAT_*) + * + * The caller should only pass a supported pixel format to this function. + * Unsupported pixel formats will generate a warning in the kernel log. + * + * Returns: + * The instance of struct drm_format_info that describes the pixel format, or + * NULL if the format is unsupported. + */ +const struct drm_format_info *drm_format_info(u32 format) +{ + const struct drm_format_info *info; + + info = __drm_format_info(format); + WARN_ON(!info); + return info; +} EXPORT_SYMBOL(drm_format_info); /** -- cgit v1.2.3