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Commit fc0524b0 authored by Gu Zheng's avatar Gu Zheng Committed by Greg Kroah-Hartman
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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: default avatarGu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9961d59d

drivers/staging/olpc_dcon/olpc_dcon.c

+4 −2
Original line number Diff line number Diff line
@@ -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",