Hi,

Le vendredi 23 mars 2018 ? 11:06 +0100, Maxime Ripard a ?crit :

On Wed, Mar 21, 2018 at 04:28:59PM +0100, Paul Kocialkowski wrote:

quoted

In order to check whether the frontend supports a specific format, an
explicit list and a related helper are introduced.

They are then used to determine whether the frontend can actually support
the requested format when it was selected to be used.

Signed-off-by: Paul Kocialkowski <redacted>
---
 drivers/gpu/drm/sun4i/sun4i_backend.c  |  5 ++++
 drivers/gpu/drm/sun4i/sun4i_frontend.c | 44 ++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/sun4i/sun4i_frontend.h |  1 +
 3 files changed, 50 insertions(+)

diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
index 7703ba989743..1fad0714c70e 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c

@@ -532,6 +532,11 @@ static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
 		struct drm_format_name_buf format_name;
 
 		if (sun4i_backend_plane_uses_frontend(plane_state)) {
+			if (!sun4i_frontend_format_is_supported(fb->format->format)) {
+				DRM_DEBUG_DRIVER("Frontend plane check failed\n");
+				return -EINVAL;
+			}
+

So you're checking if the frontend doesn't support it and if the
backend doesn't support it. Who supports it then? :)

Like I was saying, this should be moved to the previous patch, within
sun4i_backend_plane_uses_frontend.

You're right, this isn't the right place to put it.
sun4i_backend_plane_uses_frontend should definitely guarantee that the
format is supported.

quoted

+static const uint32_t sun4i_frontend_formats[] = {
+	/* RGB */
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_BGRX8888,
+	/* YUV444 */
+	DRM_FORMAT_YUV444,
+	DRM_FORMAT_YVU444,
+	/* YUV422 */
+	DRM_FORMAT_YUYV,
+	DRM_FORMAT_YVYU,
+	DRM_FORMAT_UYVY,
+	DRM_FORMAT_VYUY,
+	DRM_FORMAT_NV16,
+	DRM_FORMAT_NV61,
+	DRM_FORMAT_YUV422,
+	DRM_FORMAT_YVU422,
+	/* YUV420 */
+	DRM_FORMAT_NV12,
+	DRM_FORMAT_NV21,
+	DRM_FORMAT_YUV420,
+	DRM_FORMAT_YVU420,
+	/* YUV411 */
+	DRM_FORMAT_YUV411,
+	DRM_FORMAT_YVU411,
+};

I think this list should reflect what the driver currently supports,
not what the hardware supports.

Agreed, this should be updated with the follow-up patch that adds YUV
support.

Cheers,

Paul

-- 
Developer of free digital technology and hardware support.

Website: https://www.paulk.fr/
Coding blog: https://code.paulk.fr/
Git repositories: https://git.paulk.fr/ https://git.code.paulk.fr/
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