[PATCH 6/8] drm/ofdrm: Preallocate xfrm buffer in plane's atomic_check

[Thomas Zimmermann <tzimmermann@suse.de>]

Preallocate the xfrm buffer's storage in the plane's atomic_check
function if a format conversion will be necessary. Allows the update
to fail if no memory is available. Avoids the same allocation within
atomic_update, which may not fail.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/tiny/ofdrm.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/tiny/ofdrm.c b/drivers/gpu/drm/tiny/ofdrm.c
index 08e4b04e0590e..d81b986f5cbc6 100644
--- a/drivers/gpu/drm/tiny/ofdrm.c
+++ b/drivers/gpu/drm/tiny/ofdrm.c
@@ -759,6 +759,8 @@ static const uint64_t ofdrm_primary_plane_format_modifiers[] = {
 static int ofdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
 						   struct drm_atomic_state *new_state)
 {
+	struct drm_device *dev = plane->dev;
+	struct ofdrm_device *odev = ofdrm_device_of_dev(dev);
 	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(new_state, plane);
 	struct drm_framebuffer *new_fb = new_plane_state->fb;
 	struct drm_crtc *new_crtc = new_plane_state->crtc;
@@ -778,6 +780,15 @@ static int ofdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
 	else if (!new_plane_state->visible)
 		return 0;
 
+	if (new_fb->format != odev->format) {
+		void *buf;
+
+		/* format conversion necessary; reserve buffer */
+		buf = drm_xfrm_buf_reserve(&odev->xfrm, odev->pitch, GFP_KERNEL);
+		if (!buf)
+			return -ENOMEM;
+	}
+
 	new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_plane_state->crtc);
 
 	new_ofdrm_crtc_state = to_ofdrm_crtc_state(new_crtc_state);
-- 
2.42.0