From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>
Cc: David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
Daniel Vetter <daniel.vetter@intel.com>
Subject: [PATCH] drm/fb-helper: Add locking to sysrq handling
Date: Wed, 7 Oct 2020 15:30:35 +0200 [thread overview]
Message-ID: <20201007133036.1541639-1-daniel.vetter@ffwll.ch> (raw)
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
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>
---
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)
--
2.28.0
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next reply other threads:[~2020-10-07 13:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 13:30 Daniel Vetter [this message]
2020-10-08 9:22 ` [PATCH] drm/fb-helper: Add locking to sysrq handling Thomas Zimmermann
2020-10-08 9:29 ` Daniel Vetter
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