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Commit 4a47a0e0 authored by Bruno Prémont's avatar Bruno Prémont Committed by Florian Tobias Schandinat
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fb: sh-mobile: Fix deadlock risk between lock_fb_info() and console_lock() 



Following on Herton's patch "fb: avoid possible deadlock caused by
fb_set_suspend" which moves lock_fb_info() out of fb_set_suspend()
to its callers, correct sh-mobile's locking around call to
fb_set_suspend() and the same sort of deaklocks with console_lock()
due to order of taking the lock.

console_lock() must be taken while fb_info is already locked and fb_info
must be locked while calling fb_set_suspend().

Signed-off-by: default avatarBruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarFlorian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: stable@kernel.org
parent 9e769ff3

drivers/video/sh_mobile_hdmi.c

+26 −21
Original line number Diff line number Diff line
@@ -1111,6 +1111,7 @@ static long sh_hdmi_clk_configure(struct sh_hdmi *hdmi, unsigned long hdmi_rate, 
static void sh_hdmi_edid_work_fn(struct work_struct *work)

{

	struct sh_hdmi *hdmi = container_of(work, struct sh_hdmi, edid_work.work);

	struct fb_info *info;

	struct sh_mobile_hdmi_info *pdata = hdmi->dev->platform_data;

	struct sh_mobile_lcdc_chan *ch;

	int ret;
@@ -1123,8 +1124,9 @@ static void sh_hdmi_edid_work_fn(struct work_struct *work) 


	mutex_lock(&hdmi->mutex);



	info = hdmi->info;



	if (hdmi->hp_state == HDMI_HOTPLUG_CONNECTED) {

		struct fb_info *info = hdmi->info;

		unsigned long parent_rate = 0, hdmi_rate;



		ret = sh_hdmi_read_edid(hdmi, &hdmi_rate, &parent_rate);
@@ -1148,6 +1150,7 @@ static void sh_hdmi_edid_work_fn(struct work_struct *work) 


		ch = info->par;



		if (lock_fb_info(info)) {

			console_lock();



			/* HDMI plug in */
@@ -1157,33 +1160,35 @@ static void sh_hdmi_edid_work_fn(struct work_struct *work) 
				 * First activation with the default monitor - just turn

				 * on, if we run a resume here, the logo disappears

				 */

			if (lock_fb_info(info)) {

				info->var.width = hdmi->var.width;

				info->var.height = hdmi->var.height;

				sh_hdmi_display_on(hdmi, info);

				unlock_fb_info(info);

			}

			} else {

				/* New monitor or have to wake up */

				fb_set_suspend(info, 0);

			}



			console_unlock();

			unlock_fb_info(info);

		}

	} else {

		ret = 0;

		if (!hdmi->info)

		if (!info)

			goto out;



		hdmi->monspec.modedb_len = 0;

		fb_destroy_modedb(hdmi->monspec.modedb);

		hdmi->monspec.modedb = NULL;



		if (lock_fb_info(info)) {

			console_lock();



			/* HDMI disconnect */

		fb_set_suspend(hdmi->info, 1);

			fb_set_suspend(info, 1);



			console_unlock();

			unlock_fb_info(info);

		}

	}



out: