On Fedora 21 or 22, when the transition from the X server to the wayland compositor is done, the CRTC with the login screen is left active with a disabled fb. A cursor ioctl after the transition causes the watermarks to be updated, but due to the logic in intel_crtc_active() checking for the primary plane fb, the update considers all planes to be disabled, untimately setting the wrong watermark values and causing screen flicker. Since the crtc is active, a modeset done later is skipped and replaced with a flip, which doesn't update the watermarks. This regression was introduced somewhere between v3.16 and v3.17. Another issue prevented me from doing a full bisect, but the issue was introduced in one of the following skipped commits: commit 7707e6535f43328e05e4729ac96eee864b90e8a4 Author: Rob Clark <robdclark@xxxxxxxxx> Date: Thu Jul 17 23:30:04 2014 -0400 drm/i915: use helpers commit ca5a1b9ba0fb5291b555a23b76dbe5f6c30bfd7a Merge: c7dbc6c 3488229 Author: Dave Airlie <airlied@xxxxxxxxxx> Date: Wed Jul 9 10:38:42 2014 +1000 Merge tag 'drm-intel-next-2014-06-20' of git://anongit.freedesktop.org/drm-intel into drm-next commit c51f71679042a5f388d9580ffbede14c897f1e86 Merge: b957f45 7b3c29f Author: Dave Airlie <airlied@xxxxxxxxxx> Date: Sat Jul 19 16:43:41 2014 +1000 Merge tag 'drm-intel-next-2014-07-11' of git://anongit.freedesktop.org/drm-intel into drm-next This patch is a simplified version of the following commits: commit 3dd512fbda0d87d1c3fb44bf878b262baee98fb6 Author: Matt Roper <matthew.d.roper@xxxxxxxxx> Date: Fri Feb 27 10:12:00 2015 -0800 drm/i915: Kill intel_crtc->cursor_{width, height} (v2) commit 54da691deb123c045259ebf4f5c67381244f58f1 Author: Thomas Gummerer <t.gummerer@xxxxxxxxx> Date: Thu May 14 09:16:39 2015 +0200 drm/i915: fix screen flickering commit 3ef00284e6a48f7deb0784ccca0478ebb7d4bcfc Author: Matt Roper <matthew.d.roper@xxxxxxxxx> Date: Mon Mar 9 10:19:24 2015 -0700 drm/i915: Use crtc->state->active in ilk/skl watermark calculations (v3) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90508 Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1218688 Cc: stable@xxxxxxxxxxxxxxx Cc: Dave Airlie <airlied@xxxxxxxxx> Cc: Jani Nikula <jani.nikula@xxxxxxxxx> Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@xxxxxxxxx> --- drivers/gpu/drm/i915/intel_pm.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 24d77dd..3d67f8e 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -1898,16 +1898,24 @@ static void ilk_compute_wm_parameters(struct drm_crtc *crtc, enum pipe pipe = intel_crtc->pipe; struct drm_plane *plane; - if (!intel_crtc_active(crtc)) + if (!intel_crtc->active) return; p->active = true; p->pipe_htotal = intel_crtc->config->base.adjusted_mode.crtc_htotal; p->pixel_rate = ilk_pipe_pixel_rate(dev, crtc); - p->pri.bytes_per_pixel = crtc->primary->fb->bits_per_pixel / 8; + + + if (crtc->primary->fb) + p->pri.bytes_per_pixel = crtc->primary->fb->bits_per_pixel / 8; + else + p->pri.bytes_per_pixel = 4; + p->cur.bytes_per_pixel = 4; + p->pri.horiz_pixels = intel_crtc->config->pipe_src_w; - p->cur.horiz_pixels = intel_crtc->cursor_width; + p->cur.horiz_pixels = intel_crtc->base.cursor->state->crtc_w; + /* TODO: for now, assume primary and cursor planes are always enabled. */ p->pri.enabled = true; p->cur.enabled = true; -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html