From f08f302732c0597c83ec6b8022aa82faffb116f9 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sat, 11 Oct 2014 18:49:20 +0200 Subject: [PATCH] terminal/grdrm: force deep modeset on enter Usually, when our session is activated (or re-configurated) we should be able to try a page-flip to our buffer. The kernel driver should reject it if it is incompatible. As it turns out, drivers don't do this. Therefore, we now force a deep modeset if we're not sure what mode is set. This has the side-effect that we might get glitches on session-switches (depending on driver behavior). However, there's no way around this and it is what everyone does so far. Most drivers still detect if we keep the mode and so don't touch the clocks. Therefore, we just get a regular async flip. --- src/libsystemd-terminal/grdev-drm.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/src/libsystemd-terminal/grdev-drm.c b/src/libsystemd-terminal/grdev-drm.c index 232321c0e..dba6db269 100644 --- a/src/libsystemd-terminal/grdev-drm.c +++ b/src/libsystemd-terminal/grdev-drm.c @@ -1158,8 +1158,21 @@ static int grdrm_crtc_commit_flip(grdrm_crtc *crtc, grdev_fb *basefb) { assert(basefb); assert(pipe); - if (!crtc->applied && !grdrm_modes_compatible(&crtc->kern.mode, &crtc->set.mode)) + if (!crtc->applied) { + if (!grdrm_modes_compatible(&crtc->kern.mode, &crtc->set.mode)) + return 0; + + /* TODO: Theoretically, we should be able to page-flip to our + * framebuffer here. We didn't perform any deep modeset, but the + * DRM driver is really supposed to reject our page-flip in case + * the FB is not compatible. We then properly fall back to a + * deep modeset. + * As it turns out, drivers don't to this. Therefore, we need to + * perform a full modeset on enter now. We might avoid this in + * the future with fixed drivers.. */ + return 0; + } fb = fb_from_base(basefb); -- 2.30.2