From ccebc23b57c313229526dc76383ce82f5e0b9001 Mon Sep 17 00:00:00 2001 From: Lyude Date: Mon, 29 Aug 2016 12:31:27 -0400 Subject: drm/i915/skl: Don't try to update plane watermarks if they haven't changed i915 sometimes needs to disable planes in the middle of an atomic commit, and then reenable them later in the same commit. Because of this, we can't make the assumption that the state of the plane actually changed. Since the state of the plane hasn't actually changed, neither have it's watermarks. And if the watermarks hasn't changed then we haven't populated skl_results with anything, which means we'll end up zeroing out a plane's watermarks in the middle of the atomic commit without restoring them later. Simple reproduction recipe: - Get a SKL laptop, launch any kind of X session - Get two extra monitors - Keep hotplugging both displays (so that the display configuration jumps from 1 active pipe to 3 active pipes and back) - Eventually underrun Changes since v1: - Fix incorrect use of "it's" Changes since v2: - Add reproduction recipe Signed-off-by: Lyude Cc: Maarten Lankhorst Fixes: 62e0fb880123 ("drm/i915/skl: Update plane watermarks atomically during plane updates") Signed-off-by: Lyude Testcase: kms_plane Signed-off-by: Maarten Lankhorst Link: http://patchwork.freedesktop.org/patch/msgid/1472488288-27280-1-git-send-email-cpaul@redhat.com Cc: drm-intel-fixes@lists.freedesktop.org --- drivers/gpu/drm/i915/intel_sprite.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/i915/intel_sprite.c') diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c index 0df783a66bfb..73a521fdf1bd 100644 --- a/drivers/gpu/drm/i915/intel_sprite.c +++ b/drivers/gpu/drm/i915/intel_sprite.c @@ -292,8 +292,13 @@ skl_disable_plane(struct drm_plane *dplane, struct drm_crtc *crtc) const int pipe = intel_plane->pipe; const int plane = intel_plane->plane + 1; - skl_write_plane_wm(to_intel_crtc(crtc), &dev_priv->wm.skl_results, - plane); + /* + * We only populate skl_results on watermark updates, and if the + * plane's visiblity isn't actually changing neither is its watermarks. + */ + if (!dplane->state->visible) + skl_write_plane_wm(to_intel_crtc(crtc), + &dev_priv->wm.skl_results, plane); I915_WRITE(PLANE_CTL(pipe, plane), 0); -- cgit v1.2.3