From d5a0c816900419105a12e7471bf074319dfa34be Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@agner.ch>
Date: Tue, 8 Sep 2020 16:16:54 +0200
Subject: drm: mxsfb: check framebuffer pitch
Git-commit: d5a0c816900419105a12e7471bf074319dfa34be
Patch-mainline: v5.10-rc1
References: bsc#1129770
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>
Link: https://patchwork.freedesktop.org/patch/msgid/20200908141654.266836-1-stefan@agner.ch
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/gpu/drm/mxsfb/mxsfb_drv.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -34,6 +34,7 @@
#include <drm/drm_crtc_helper.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fb_cma_helper.h>
+#include <drm/drm_fourcc.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_of.h>
@@ -92,8 +93,26 @@ void mxsfb_disable_axi_clk(struct 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,
};