From 84014b0a39eef6df4a26f8afabf2b50bd376d515 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Tue, 17 Oct 2017 17:27:14 +0200 Subject: [PATCH] drm/atomic-helper: check that drivers call drm_crtc_vblank_off MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit At least when they have vblank support they need to call this, or the vblank core will happily call into their crtc->enable_vblank callback even when the crtc is off. Which leads to a boom when the clocks are off on most hardware (besides the inevitable confusion in the book-keeping). The consistency checks in drm_vblank.c will then make sure that vblank_off/on calls are balanced, and if drivers forget to re-enable it all the commits will stall, so I think we're covered. It'd be nice to be able to place this check outside of commit helpers, but tha's not really possible (due to nonblocking commits and all that). Placing it into atomic helpers should at least cover most drivers. Also note that vblank support is still optional (for virtual drivers, which tend to not have this), check for that. v2: Fixup the handling for vblank_put (Rob). Cc: Rob Clark Tested-by: Rob Clark Cc: Ville Syrjälä Reviewed-by: Ville Syrjälä Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20171017152714.6849-1-daniel.vetter@ffwll.ch --- drivers/gpu/drm/drm_atomic_helper.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 3472d9ae8b95..27dc6838533a 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -860,6 +860,7 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state) for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) { const struct drm_crtc_helper_funcs *funcs; + int ret; /* Shut down everything that needs a full modeset. */ if (!drm_atomic_crtc_needs_modeset(new_crtc_state)) @@ -883,6 +884,14 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state) funcs->disable(crtc); else funcs->dpms(crtc, DRM_MODE_DPMS_OFF); + + if (!(dev->irq_enabled && dev->num_crtcs)) + continue; + + ret = drm_crtc_vblank_get(crtc); + WARN_ONCE(ret != -EINVAL, "driver forgot to call drm_crtc_vblank_off()\n"); + if (ret == 0) + drm_crtc_vblank_put(crtc); } } -- 2.30.2