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drm/fb-helper: Add locking to sysrq handling

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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 <tzimmermann@suse.de>
Signed-off-by: Daniel 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
This commit is contained in:
Daniel Vetter 2020-10-07 15:30:35 +02:00
parent 5a3884320a
commit a76fa3540f
1 changed files with 5 additions and 21 deletions
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26
drivers/gpu/drm/drm_fb_helper.c
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@ -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)