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Subject[PATCH 1/2] simplefb: fix unmapping fb during destruction
Date
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 <teg@jklm.no>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
---
Hi

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.

Thanks
David

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->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
- 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) {
framebuffer_release(info);
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);
framebuffer_release(info);
return ret;
}
--
1.8.4


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