[Intel-gfx] [PATCH i-g-t 1/2] lib: Check format of framebuffer before SetPlane

[Tomeu Vizoso]

Avoid setting a framebuffer in a format that the plane doesn't support,
so we have better debug output in IGT and we don't have to dig into
dmesg files to find out what's going on.

I found this issue when kms_plane_scaling tried to use a cursor plane as
a regular one in a Skylake machine with just one overlay.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso at collabora.com>
---
 lib/igt_kms.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/lib/igt_kms.c b/lib/igt_kms.c
index 989704e14803..3234fa1bbdc4 100644
--- a/lib/igt_kms.c
+++ b/lib/igt_kms.c
@@ -1670,6 +1670,14 @@ static uint32_t igt_plane_get_fb_id(igt_plane_t *plane)
 		return 0;
 }
 
+static uint32_t igt_plane_get_fb_format(igt_plane_t *plane)
+{
+	if (plane->fb)
+		return plane->fb->drm_format;
+	else
+		return 0;
+}
+
 static uint32_t igt_plane_get_fb_gem_handle(igt_plane_t *plane)
 {
 	if (plane->fb)
@@ -1678,6 +1686,28 @@ static uint32_t igt_plane_get_fb_gem_handle(igt_plane_t *plane)
 		return 0;
 }
 
+static bool igt_plane_supports_format(igt_plane_t *plane, uint32_t format)
+{
+	int i;
+
+	for (i = 0; i < plane->drm_plane->count_formats; i++) {
+		if (format == plane->drm_plane->formats[i])
+			return true;
+	}
+
+	igt_debug("Plane %d in pipe %s doesn't support format %s.\n",
+		  plane->index,
+	          kmstest_pipe_name(plane->pipe->pipe),
+	          igt_format_str(format));
+
+	igt_debug("Formats supported are:");
+	for (i = 0; i < plane->drm_plane->count_formats; i++)
+		igt_debug(" %s", igt_format_str(plane->drm_plane->formats[i]));
+	igt_debug(".\n");
+
+	return false;
+}
+
 #define CHECK_RETURN(r, fail) {	\
 	if (r && !fail)		\
 		return r;	\
@@ -1772,6 +1802,7 @@ static int igt_drm_plane_commit(igt_plane_t *plane,
 	int32_t crtc_y;
 	uint32_t crtc_w;
 	uint32_t crtc_h;
+	uint32_t format;
 
 	igt_assert(plane->drm_plane);
 
@@ -1821,6 +1852,10 @@ static int igt_drm_plane_commit(igt_plane_t *plane,
 		    src_x >> 16, src_y >> 16, src_w >> 16, src_h >> 16,
 		    crtc_x, crtc_y, crtc_w, crtc_h);
 
+		/* it's an error to try an unsupported format */
+		format = igt_plane_get_fb_format(plane);
+		igt_assert(igt_plane_supports_format(plane, format));
+
 		ret = drmModeSetPlane(display->drm_fd,
 				      plane->drm_plane->plane_id,
 				      crtc_id,
-- 
2.7.4