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staging/olpc_docn: reorder the lock sequence to avoid potential dead lock 

The lock sequence of dcon_blank_fb(fb_info->lock ---> console_lock) is against
with the one of console_callback(console_lock ---> fb_info->lock), it'll
lead to a potential dead lock, so reorder the lock sequence of dcon_blank_fb
to avoid the potential dead lock.

Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gu Zheng 2013-10-31 18:33:01 +08:00 committed by Greg Kroah-Hartman
parent 9961d59d3f
commit fc0524b098
1 changed files with 4 additions and 2 deletions
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6
drivers/staging/olpc_dcon/olpc_dcon.c
View File

@ -255,17 +255,19 @@ static bool dcon_blank_fb(struct dcon_priv *dcon, bool blank)
{
int err;
console_lock();
if (!lock_fb_info(dcon->fbinfo)) {
console_unlock();
dev_err(&dcon->client->dev, "unable to lock framebuffer\n");
return false;
}
console_lock();
dcon->ignore_fb_events = true;
err = fb_blank(dcon->fbinfo,
blank ? FB_BLANK_POWERDOWN : FB_BLANK_UNBLANK);
dcon->ignore_fb_events = false;
console_unlock();
unlock_fb_info(dcon->fbinfo);
console_unlock();
if (err) {
dev_err(&dcon->client->dev, "couldn't %sblank framebuffer\n",