[PATCH 3/4] drm/i915: don't force full modeset if primary plane is disabled (v2)

Matt Roper
2014-05-15T16:13:54Z

In a future patch, we'll allow the primary plane to be disabled by
userspace via the universal plane API. If a modeset is requested while
the primary plane is disabled, crtc->primary->fb will be NULL which
generally triggers a full modeset (except in fastboot situations). If
we detect that the crtc is active, but there's no primary plane fb,
we should still allow a simple plane update rather than a full modeset
if the mode isn't actually changing (after re-enabling the primary plane
of course).

v2:
- Enable plane after set_base to avoid enabling the plane if set_base
fails, and to make flip+enable atomic (suggested by Ville)
- Drop BUG to WARN if we somehow enter the 'fb_changed' modeset case
with the crtc disabled (suggested by Ville)

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0f8f9bc..3aedc64 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10417,12 +10417,17 @@ intel_set_config_compute_mode_changes(struct drm_mode_set *set,
if (is_crtc_connector_off(set)) {
config->mode_changed = true;
} else if (set->crtc->primary->fb != set->fb) {
- /* If we have no fb then treat it as a full mode set */
+ /*
+ * If we have no fb, we can only flip as long as the crtc is
+ * active, otherwise we need a full mode set. The crtc may
+ * be active if we've only disabled the primary plane, or
+ * in fastboot situations.
+ */
if (set->crtc->primary->fb == NULL) {
struct intel_crtc *intel_crtc =
to_intel_crtc(set->crtc);

- if (intel_crtc->active && i915.fastboot) {
+ if (intel_crtc->active) {
DRM_DEBUG_KMS("crtc has no fb, will flip\n");
config->fb_changed = true;
} else {
@@ -10660,10 +10665,24 @@ static int intel_crtc_set_config(struct drm_mode_set *set)
ret = intel_set_mode(set->crtc, set->mode,
set->x, set->y, set->fb);
} else if (config->fb_changed) {
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct intel_crtc *intel_crtc = to_intel_crtc(set->crtc);
+
intel_crtc_wait_for_pending_flips(set->crtc);

ret = intel_pipe_set_base(set->crtc,
set->x, set->y, set->fb);
+
+ /*
+ * We need to make sure the primary plane is re-enabled if it
+ * has previously been turned off.
+ */
+ if (!intel_crtc->primary_enabled && ret == 0) {
+ WARN_ON(!intel_crtc->active);
+ intel_enable_primary_hw_plane(dev_priv, intel_crtc->plane,
+ intel_crtc->pipe);
+ }
+
/*
* In the fastboot case this may be our only check of the
* state after boot. It would be better to only do it on
--
1.8.5.1