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Subject[PATCH 1/2] drm/atomic: Allow vblank-enabled + self-refresh "disable"
Date
The self-refresh helper framework overloads "disable" to sometimes mean
"go into self-refresh mode," and this mode activates automatically
(e.g., after some period of unchanging display output). In such cases,
the display pipe is still considered "on", and user-space is not aware
that we went into self-refresh mode. Thus, users may expect that
vblank-related features (such as DRM_IOCTL_WAIT_VBLANK) still work
properly.

However, we trigger the WARN_ONCE() here if a CRTC driver tries to leave
vblank enabled here.

Add a new exception, such that we allow CRTCs to be "disabled" (with
self-refresh active) with vblank interrupts still enabled.

Cc: <stable@vger.kernel.org> # dependency for subsequent patch
Signed-off-by: Brian Norris <briannorris@chromium.org>
---

drivers/gpu/drm/drm_atomic_helper.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index d579fd8f7cb8..7b5eddadebd5 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -1207,6 +1207,12 @@ disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)

if (!drm_dev_has_vblank(dev))
continue;
+ /*
+ * Self-refresh is not a true "disable"; let vblank remain
+ * enabled.
+ */
+ if (new_crtc_state->self_refresh_active)
+ continue;

ret = drm_crtc_vblank_get(crtc);
WARN_ONCE(ret != -EINVAL, "driver forgot to call drm_crtc_vblank_off()\n");
--
2.39.0.314.g84b9a713c41-goog
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