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 <lyude@xxxxxxxxxx> Cc: Daniel Vetter <daniel@xxxxxxxx> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> --- 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 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
