drm/imx: Add 8 pixel alignment fix

Some standard resolutions like 1366x768 do not work properly with
i.MX6 SoCs, since the horizontal resolution needs to be aligned
to 8 pixels (so 1360x768 or 1368x768 would work).

This patch allocates framebuffers allocated to 8 pixels. The extra
time required to send the extra pixels are removed from the blank
time. In order to expose the correct display size to userspace,
the stride is increased without increasing the width.

Without this patch systems with this display resolution hang
indefinitely during boot up.

Suggested-by: Boris Brezillon <[email protected]>
Signed-off-by: Sebastian Reichel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Philipp Zabel <[email protected]>

1 files changed, 18 insertions, 1 deletions

diff --git a/drivers/gpu/drm/imx/imx-drm-core.c b/drivers/gpu/drm/imx/imx-drm-core.c
index be6001d8c984..3709d343784a 100644
--- a/drivers/gpu/drm/imx/imx-drm-core.c
+++ b/drivers/gpu/drm/imx/imx-drm-core.c
@@ -147,9 +147,26 @@ static const struct drm_ioctl_desc imx_drm_ioctls[] = {
 	/* none so far */
 };
 
+static int imx_drm_dumb_create(struct drm_file *file_priv,
+			       struct drm_device *drm,
+			       struct drm_mode_create_dumb *args)
+{
+	u32 width = args->width;
+	int ret;
+
+	args->width = ALIGN(width, 8);
+
+	ret = drm_gem_cma_dumb_create(file_priv, drm, args);
+	if (ret)
+		return ret;
+
+	args->width = width;
+	return ret;
+}
+
 static const struct drm_driver imx_drm_driver = {
 	.driver_features	= DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
-	DRM_GEM_CMA_DRIVER_OPS,
+	DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE(imx_drm_dumb_create),
 	.ioctls			= imx_drm_ioctls,
 	.num_ioctls		= ARRAY_SIZE(imx_drm_ioctls),
 	.fops			= &imx_drm_driver_fops,