This got me confused for a bit while looking over this code: I had been
planning on adding some blocking function calls into this function, but
seeing the irqsave/irqrestore variants of spin_(un)lock() didn't make it
very clear whether or not that would actually be safe.
So I went ahead and reviewed every single driver in the kernel that uses
this function, and they all fall into three categories:
* Driver probe code
* ->atomic_disable() callbacks
* Legacy modesetting callbacks
All of these will be guaranteed to have IRQs enabled, which means it's
perfectly safe to block here. Just to make things a little less
confusing to others in the future, let's switch over to
spin_lock_irq()/spin_unlock_irq() to make that fact a little more
obvious.
Signed-off-by: Lyude Paul <ly...@redhat.com>
Reviewed-by: Daniel Vetter <dan...@ffwll.ch>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
drivers/gpu/drm/drm_vblank.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index ce5c1e1d29963..e895f5331fdb4 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -1283,13 +1283,12 @@ void drm_crtc_vblank_off(struct drm_crtc *crtc)
struct drm_pending_vblank_event *e, *t;
ktime_t now;
- unsigned long irqflags;
u64 seq;
if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
return;
- spin_lock_irqsave(&dev->event_lock, irqflags);
+ spin_lock_irq(&dev->event_lock);
spin_lock(&dev->vbl_lock);
drm_dbg_vbl(dev, "crtc %d, vblank enabled %d, inmodeset %d\n",
@@ -1325,7 +1324,7 @@ void drm_crtc_vblank_off(struct drm_crtc *crtc)
drm_vblank_put(dev, pipe);
send_vblank_event(dev, e, seq, now);
}
- spin_unlock_irqrestore(&dev->event_lock, irqflags);
+ spin_unlock_irq(&dev->event_lock);
/* Will be reset by the modeset helpers when re-enabling the crtc by
* calling drm_calc_timestamping_constants(). */
--
2.26.2
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