Patch "drm: mxsfb: check framebuffer pitch" has been added to the 5.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm: mxsfb: check framebuffer pitch

to the 5.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-mxsfb-check-framebuffer-pitch.patch
and it can be found in the queue-5.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3e7c51ac0dffac7b83badd04ba092d3878bd4fd7
Author: Stefan Agner <stefan@xxxxxxxx>
Date:   Tue Sep 8 16:16:54 2020 +0200

    drm: mxsfb: check framebuffer pitch
    
    [ Upstream commit d5a0c816900419105a12e7471bf074319dfa34be ]
    
    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@xxxxxxxx>
    Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
    Link: https://patchwork.freedesktop.org/patch/msgid/20200908141654.266836-1-stefan@xxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 508764fccd27d..27ccfa531d31f 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -26,6 +26,7 @@
 #include <drm/drm_drv.h>
 #include <drm/drm_fb_cma_helper.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>
@@ -92,8 +93,26 @@ 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,
 };