Commit a76fa354 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/fb-helper: Add locking to sysrq handling 



We didn't take the kernel_fb_helper_lock mutex, which protects that
code. While at it, simplify the code
- inline the function (originally shared with kgdb I think)
- drop the error tracking and all the complications
- drop the pointless early out, it served nothing

Acked-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201007133036.1541639-1-daniel.vetter@ffwll.ch
parent 5a388432

drivers/gpu/drm/drm_fb_helper.c

+5 −21
Original line number Diff line number Diff line
@@ -281,18 +281,12 @@ int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper) 
EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);



#ifdef CONFIG_MAGIC_SYSRQ

/*

 * restore fbcon display for all kms driver's using this helper, used for sysrq

 * and panic handling.

 */

static bool drm_fb_helper_force_kernel_mode(void)

/* emergency restore, don't bother with error reporting */

static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)

{

	bool ret, error = false;

	struct drm_fb_helper *helper;



	if (list_empty(&kernel_fb_helper_list))

		return false;



	mutex_lock(&kernel_fb_helper_lock);

	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {

		struct drm_device *dev = helper->dev;
@@ -300,22 +294,12 @@ static bool drm_fb_helper_force_kernel_mode(void) 
			continue;



		mutex_lock(&helper->lock);

		ret = drm_client_modeset_commit_locked(&helper->client);

		if (ret)

			error = true;

		drm_client_modeset_commit_locked(&helper->client);

		mutex_unlock(&helper->lock);

	}

	return error;

	mutex_unlock(&kernel_fb_helper_lock);

}



static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)

{

	bool ret;



	ret = drm_fb_helper_force_kernel_mode();

	if (ret == true)

		DRM_ERROR("Failed to restore crtc configuration\n");

}

static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);



static void drm_fb_helper_sysrq(int dummy1)

CRA Git | Maintained and supported by SUSTech CRA and CCSE