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authorDaniel Vetter <daniel.vetter@ffwll.ch>2019-05-28 11:02:56 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2019-06-12 20:30:00 +0200
commitde29ae5c092bd9a5360cfabf174b0f783248d278 (patch)
treecaebbd07fb21b024914cefb2aaea588c52e3a28e /drivers/video
parent7a625549ea8c14be70bc7cfaf30215401bba6da0 (diff)
downloadlinux-de29ae5c092bd9a5360cfabf174b0f783248d278.tar.bz2
fbmem: pull fbcon_fb_blanked out of fb_blank
There's a callchain of: fbcon_fb_blanked -> do_(un)blank_screen -> consw->con_blank -> fbcon_blank -> fb_blank Things don't go horribly wrong because the BKL console_lock safes the day, but that's about it. And the seeming recursion is broken in 2 ways: - Starting from the fbdev ioctl we set FBINFO_MISC_USEREVENT, which tells the fbcon_blank code to not call fb_blank. This was required to not deadlock when recursing on the fb_notifier_chain mutex. - Starting from the con_blank hook we're getting saved by the console_blanked checks in do_blank/unblank_screen. Or at least that's my theory. Anyway, recursion isn't awesome, so let's stop it. Breaking the recursion avoids the need to be in the FBINFO_MISC_USEREVENT critical section, so lets move it out of that too. The astute reader will notice that fb_blank seems to require lock_fb_info(), which the fbcon code seems to ignore. I have no idea how to fix that problem, so let's keep ignoring it. v2: I forgot the sysfs blanking code. v3: Fix typo in callchain in the commmit message (Sam). Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: "Michał Mirosław" <mirq-linux@rere.qmqm.pl> Cc: Peter Rosin <peda@axentia.se> Cc: Hans de Goede <hdegoede@redhat.com> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Rob Clark <robdclark@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-26-daniel.vetter@ffwll.ch
Diffstat (limited to 'drivers/video')
-rw-r--r--drivers/video/fbdev/core/fbmem.c4
-rw-r--r--drivers/video/fbdev/core/fbsysfs.c8
2 files changed, 9 insertions, 3 deletions
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 9366fbe99a58..d6713dce9e31 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1068,7 +1068,6 @@ fb_blank(struct fb_info *info, int blank)
event.data = &blank;
early_ret = fb_notifier_call_chain(FB_EARLY_EVENT_BLANK, &event);
- fbcon_fb_blanked(info, blank);
if (info->fbops->fb_blank)
ret = info->fbops->fb_blank(blank, info);
@@ -1198,6 +1197,9 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
info->flags |= FBINFO_MISC_USEREVENT;
ret = fb_blank(info, arg);
info->flags &= ~FBINFO_MISC_USEREVENT;
+
+ /* might again call into fb_blank */
+ fbcon_fb_blanked(info, arg);
unlock_fb_info(info);
console_unlock();
break;
diff --git a/drivers/video/fbdev/core/fbsysfs.c b/drivers/video/fbdev/core/fbsysfs.c
index f80d5b3a7797..6e39066774a6 100644
--- a/drivers/video/fbdev/core/fbsysfs.c
+++ b/drivers/video/fbdev/core/fbsysfs.c
@@ -14,6 +14,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fb.h>
+#include <linux/fbcon.h>
#include <linux/console.h>
#include <linux/module.h>
@@ -301,12 +302,15 @@ static ssize_t store_blank(struct device *device,
{
struct fb_info *fb_info = dev_get_drvdata(device);
char *last = NULL;
- int err;
+ int err, arg;
+ arg = simple_strtoul(buf, &last, 0);
console_lock();
fb_info->flags |= FBINFO_MISC_USEREVENT;
- err = fb_blank(fb_info, simple_strtoul(buf, &last, 0));
+ err = fb_blank(fb_info, arg);
fb_info->flags &= ~FBINFO_MISC_USEREVENT;
+ /* might again call into fb_blank */
+ fbcon_fb_blanked(fb_info, arg);
console_unlock();
if (err < 0)
return err;