The lcdif IP does not support a framebuffer pitch (stride) other than
framebuffer width. Check for equality and reject the framebuffer
otherwise.
This prevents a distorted picture when using 640x800 and running the
Mesa graphics stack. Mesa tires to use a cache aligned stride, which
leads at that particular resolution to width != stride. Currently
Mesa has no fallback behavior, but rejecting this configuration allows
userspace to handle the issue correctly.
Signed-off-by: Stefan Agner <ste...@agner.ch>
---
drivers/gpu/drm/mxsfb/mxsfb_drv.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 8c549c3931af..fa6798d21029 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -21,6 +21,7 @@
#include <drm/drm_connector.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
+#include <drm/drm_fourcc.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_irq.h>
@@ -81,8 +82,26 @@ void mxsfb_disable_axi_clk(struct mxsfb_drm_private *mxsfb)
clk_disable_unprepare(mxsfb->clk_axi);
}
+static struct drm_framebuffer *
+mxsfb_fb_create(struct drm_device *dev, struct drm_file *file_priv,
+ const struct drm_mode_fb_cmd2 *mode_cmd)
+{
+ const struct drm_format_info *info;
+
+ info = drm_get_format_info(dev, mode_cmd);
+ if (!info)
+ return ERR_PTR(-EINVAL);
+
+ if (mode_cmd->width * info->cpp[0] != mode_cmd->pitches[0]) {
+ dev_dbg(dev->dev, "Invalid pitch: fb width must match pitch\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ return drm_gem_fb_create(dev, file_priv, mode_cmd);
+}
+
static const struct drm_mode_config_funcs mxsfb_mode_config_funcs = {
- .fb_create = drm_gem_fb_create,
+ .fb_create = mxsfb_fb_create,
.atomic_check = drm_atomic_helper_check,
.atomic_commit = drm_atomic_helper_commit,
};
--
2.28.0
