From a76fa3540fc33de4718b386aea37ed4a7236d253 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Wed, 7 Oct 2020 15:30:35 +0200 Subject: [PATCH] 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: Thomas Zimmermann Signed-off-by: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20201007133036.1541639-1-daniel.vetter@ffwll.ch --- drivers/gpu/drm/drm_fb_helper.c | 26 +++++--------------------- 1 file changed, 5 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 8697554ccd41..c2f72bb6afb1 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -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) -- 2.11.0