drm/atomic: Introduce drm_atomic_helper_shutdown

The trouble here is that it does multiple atomic commits under one
drm_modeset_lock_all, which breaks the behind-the-scenes acquire
context magic that function pulls off. It's much better to have one
overall atomic commit. That we still have multiple atomic commits
prevents us from adding some pretty useful debug checks to the atomic
machinery.

Hence it is really a bad idea to call the legacy
drm_crtc_force_disable_all() function. There's 2 atomic drivers using
this still, nouveau and tinydrm. To fix this, introduce a new
drm_atomic_helper_shutdown() by extracting the code from i915.

While at it improve kernel-doc and catch future offenders by
sprinkling a WARN_ON into the legacy function. We should probably move
those into the legacy modeset helpers, too ...

v2: Make it compile on arm drivers too (Noralf).

v3: Correct kerneldoc to point at _disable_all().

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Ben Skeggs <bskeggs@redhat.com>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170321164149.31531-1-daniel.vetter@ffwll.ch

1 files changed, 1 insertions, 19 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 03d9e45694c9..98b17070a123 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1307,8 +1307,6 @@ void i915_driver_unload(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct pci_dev *pdev = dev_priv->drm.pdev;
-	struct drm_modeset_acquire_ctx ctx;
-	int ret;
 
 	intel_fbdev_fini(dev);
 
@@ -1317,23 +1315,7 @@ void i915_driver_unload(struct drm_device *dev)
 
 	intel_display_power_get(dev_priv, POWER_DOMAIN_INIT);
 
-	drm_modeset_acquire_init(&ctx, 0);
-	while (1) {
-		ret = drm_modeset_lock_all_ctx(dev, &ctx);
-		if (!ret)
-			ret = drm_atomic_helper_disable_all(dev, &ctx);
-
-		if (ret != -EDEADLK)
-			break;
-
-		drm_modeset_backoff(&ctx);
-	}
-
-	if (ret)
-		DRM_ERROR("Disabling all crtc's during unload failed with %i\n", ret);
-
-	drm_modeset_drop_locks(&ctx);
-	drm_modeset_acquire_fini(&ctx);
+	drm_atomic_helper_shutdown(dev);
 
 	intel_gvt_cleanup(dev_priv);