From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: [PATCH] drm/i915: Asynchronously perform the set-base for a simple modeset Date: Fri, 9 Aug 2013 15:13:22 +0100 Message-ID: <1376057602-15233-1-git-send-email-chris@chris-wilson.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from fireflyinternet.com (s16502780.onlinehome-server.info [87.106.93.118]) by gabe.freedesktop.org (Postfix) with ESMTP id 9D05BE691D for ; Fri, 9 Aug 2013 07:13:34 -0700 (PDT) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org A simple modeset, where we only wish to switch over to a new framebuffer such as the transition from fbcon to X, takes around 30-60ms. This is due to three factors: 1. We need to make sure the fb->obj is in the display domain, which incurs a cache flush to ensure no dirt is left on the scanout. 2. We need to flush any pending rendering before performing the mmio so that the frame is complete before it is shown. 3. We currently wait for the vblank after the mmio to be sure that the old fb is no longer being shown before releasing it. (1) can only be eliminated by userspace preparing the fb->obj in advance to already be in the display domain. This can be done through use of the create2 ioctl, or by reusing an existing fb->obj. However, (2) and (3) are already solved by the existing page flip mechanism, and it is surprisingly trivial to wire them up for use in the set-base fast path. Though it can be argued that this represents a subtle ABI break in that the set_config ioctl now returns before the old framebuffer is unpinned. The danger is that userspace will start to modify it before it is no longer being shown, however we should be able to prevent that through proper domain tracking. By combining all of the above, we can achieve an instaneous set_config: [ 6.601] (II) intel(0): switch to mode 2560x1440@60.0 on pipe 0 using DP2, position (0, 0), rotation normal [ 6.601] (II) intel(0): Setting screen physical size to 677 x 381 Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/intel_display.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 809b968..c6eea51 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -9077,10 +9077,13 @@ 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) { - intel_crtc_wait_for_pending_flips(set->crtc); - - ret = intel_pipe_set_base(set->crtc, - set->x, set->y, set->fb); + if (to_intel_framebuffer(set->fb)->obj->ring == NULL || + save_set.x != set->x || save_set.y != set->y || + intel_crtc_page_flip(set->crtc, set->fb, NULL)) { + intel_crtc_wait_for_pending_flips(set->crtc); + ret = intel_pipe_set_base(set->crtc, + set->x, set->y, set->fb); + } } if (ret) { -- 1.8.1.2