[lkml]   [2013]   [Oct]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 1/2] simplefb: fix unmapping fb during destruction
Unfortunately, fbdev does not create its own "struct device" for
framebuffers. Instead, it attaches to the device of the parent layer. This
has the side-effect that devm_* managed resources are not cleaned up on
framebuffer-destruction but rather during destruction of the
parent-device. In case of fbdev this might be too late, though.
remove_conflicting_framebuffer() may remove fbdev devices but keep the
parent device as it is.

Therefore, we now use plain ioremap() and unmap the framebuffer in the
fb_destroy() callback. Note that we must not free the device here as this
might race with the parent-device removal. Instead, we rely on
unregister_framebuffer() as barrier and we're safe.

Reported-by: Tom Gundersen <>
Signed-off-by: David Herrmann <>

I know that simplefb was supposed to stay "as simple as possible" but I really
think this series is the last set of fixes I have. Unfortunately framebuffer DRM
handover is mandatory so we cannot ignore it in simplefb.

Both patches are not critical at all and are targeted at 3.13-rc1.


drivers/video/simplefb.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/video/simplefb.c b/drivers/video/simplefb.c
index 8d78106..74b016c 100644
--- a/drivers/video/simplefb.c
+++ b/drivers/video/simplefb.c
@@ -66,8 +66,15 @@ static int simplefb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
return 0;

+static void simplefb_destroy(struct fb_info *info)
+ if (info->screen_base)
+ iounmap(info->screen_base);
static struct fb_ops simplefb_ops = {
.owner = THIS_MODULE,
+ .fb_destroy = simplefb_destroy,
.fb_setcolreg = simplefb_setcolreg,
.fb_fillrect = cfb_fillrect,
.fb_copyarea = cfb_copyarea,
@@ -212,8 +219,8 @@ static int simplefb_probe(struct platform_device *pdev)

info->fbops = &simplefb_ops;
- info->screen_base = devm_ioremap(&pdev->dev, info->fix.smem_start,
- info->fix.smem_len);
+ info->screen_base = ioremap(info->fix.smem_start,
+ info->fix.smem_len);
if (!info->screen_base) {
return -ENODEV;
@@ -223,6 +230,7 @@ static int simplefb_probe(struct platform_device *pdev)
ret = register_framebuffer(info);
if (ret < 0) {
dev_err(&pdev->dev, "Unable to register simplefb: %d\n", ret);
+ iounmap(info->screen_base);
return ret;

 \ /
  Last update: 2013-10-02 17:41    [W:0.093 / U:0.056 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site