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 tries 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.
Fixes: 45d59d704080 ("drm: Add new driver for MXSFB controller") Signed-off-by: Stefan Agner stefan@agner.ch Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- Changes in v3: - Fix typo in commit message - Add fixes tag
Changes in v2: - Validate pitch in fb_create callback
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..35122aef037b 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, };