[systemd-commits] src/libsystemd-terminal

[David Herrmann]

 src/libsystemd-terminal/grdev-drm.c |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

New commits:
commit f08f302732c0597c83ec6b8022aa82faffb116f9
Author: David Herrmann <dh.herrmann at gmail.com>
Date:   Sat Oct 11 18:49:20 2014 +0200

    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.

diff --git a/src/libsystemd-terminal/grdev-drm.c b/src/libsystemd-terminal/grdev-drm.c
index 232321c..dba6db2 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);