From aec3f44651998211d559b474bb830aad65680a62 Mon Sep 17 00:00:00 2001

From: David Herrmann <dh.herrmann@gmail.com>

Date: Thu, 2 Oct 2014 17:59:26 +0200

Subject: [PATCH] terminal/drm: provide pipe->target() callback

Instead of looking for available back-buffers on each operation, set it to

NULL and wait for the next frame request. It will call back into the pipe

to request the back-buffer via ->target(), where we can do the same and

look for an available backbuffer.

This simplifies the code and avoids double lookups if we run short of

buffers.

---

 src/libsystemd-terminal/grdev-drm.c | 98 ++++++++++++++++---------------------

 src/libsystemd-terminal/grdev.c     |  2 +

 2 files changed, 44 insertions(+), 56 deletions(-)

diff --git a/src/libsystemd-terminal/grdev-drm.c b/src/libsystemd-terminal/grdev-drm.c

index 6b130116d7..57b930bc0f 100644

--- a/src/libsystemd-terminal/grdev-drm.c

+++ b/src/libsystemd-terminal/grdev-drm.c

@@ -1095,19 +1095,19 @@ static void grdrm_crtc_expose(grdrm_crtc *crtc) {

         grdev_pipe_ready(&crtc->pipe->base, true);

 }

-static void grdrm_crtc_commit_deep(grdrm_crtc *crtc, grdev_fb **slot) {

+static void grdrm_crtc_commit_deep(grdrm_crtc *crtc, grdev_fb *basefb) {

         struct drm_mode_crtc set_crtc = { .crtc_id = crtc->object.id };

         grdrm_card *card = crtc->object.card;

         grdrm_pipe *pipe = crtc->pipe;

-        grdrm_fb *fb = fb_from_base(*slot);

-        size_t i;

+        grdrm_fb *fb;

         int r;

         assert(crtc);

-        assert(slot);

-        assert(*slot);

+        assert(basefb);

         assert(pipe);

+        fb = fb_from_base(basefb);

+

         set_crtc.set_connectors_ptr = PTR_TO_UINT64(crtc->set.connectors);

         set_crtc.count_connectors = crtc->set.n_connectors;

         set_crtc.fb_id = fb->id;

@@ -1132,7 +1132,7 @@ static void grdrm_crtc_commit_deep(grdrm_crtc *crtc, grdev_fb **slot) {

                 crtc->applied = true;

         }

-        *slot = NULL;

+        pipe->base.back = NULL;

         pipe->base.front = &fb->base;

         fb->flipid = 0;

         ++pipe->counter;

@@ -1144,40 +1144,25 @@ static void grdrm_crtc_commit_deep(grdrm_crtc *crtc, grdev_fb **slot) {

          * To avoid duplicating that everywhere, we schedule our own

          * timer and raise a fake FRAME event when it fires. */

         grdev_pipe_schedule(&pipe->base, 1);

-

-        if (!pipe->base.back) {

-                for (i = 0; i < pipe->base.max_fbs; ++i) {

-                        if (!pipe->base.fbs[i])

-                                continue;

-

-                        fb = fb_from_base(pipe->base.fbs[i]);

-                        if (&fb->base == pipe->base.front)

-                                continue;

-

-                        fb->flipid = 0;

-                        pipe->base.back = &fb->base;

-                        break;

-                }

-        }

 }

-static int grdrm_crtc_commit_flip(grdrm_crtc *crtc, grdev_fb **slot) {

+static int grdrm_crtc_commit_flip(grdrm_crtc *crtc, grdev_fb *basefb) {

         struct drm_mode_crtc_page_flip page_flip = { .crtc_id = crtc->object.id };

         grdrm_card *card = crtc->object.card;

         grdrm_pipe *pipe = crtc->pipe;

-        grdrm_fb *fb = fb_from_base(*slot);

+        grdrm_fb *fb;

         uint32_t cnt;

-        size_t i;

         int r;

         assert(crtc);

-        assert(slot);

-        assert(*slot);

+        assert(basefb);

         assert(pipe);

         if (!crtc->applied && !grdrm_modes_compatible(&crtc->kern.mode, &crtc->set.mode))

                 return 0;

+        fb = fb_from_base(basefb);

+

         cnt = ++pipe->counter ? : ++pipe->counter;

         page_flip.fb_id = fb->id;

         page_flip.flags = DRM_MODE_PAGE_FLIP_EVENT;

@@ -1209,29 +1194,13 @@ static int grdrm_crtc_commit_flip(grdrm_crtc *crtc, grdev_fb **slot) {

         pipe->base.flip = false;

         pipe->counter = cnt;

         fb->flipid = cnt;

-        *slot = NULL;

+        pipe->base.back = NULL;

         /* Raise fake FRAME event if it takes longer than 2

          * frames to receive the pageflip event. We assume the

          * queue ran over or some other error happened. */

         grdev_pipe_schedule(&pipe->base, 2);

-        if (!pipe->base.back) {

-                for (i = 0; i < pipe->base.max_fbs; ++i) {

-                        if (!pipe->base.fbs[i])

-                                continue;

-

-                        fb = fb_from_base(pipe->base.fbs[i]);

-                        if (&fb->base == pipe->base.front)

-                                continue;

-                        if (fb->flipid)

-                                continue;

-

-                        pipe->base.back = &fb->base;

-                        break;

-                }

-        }

-

         return 1;

 }

@@ -1239,7 +1208,7 @@ static void grdrm_crtc_commit(grdrm_crtc *crtc) {

         struct drm_mode_crtc set_crtc = { .crtc_id = crtc->object.id };

         grdrm_card *card = crtc->object.card;

         grdrm_pipe *pipe;

-        grdev_fb **slot;

+        grdev_fb *fb;

         int r;

         assert(crtc);

@@ -1280,19 +1249,19 @@ static void grdrm_crtc_commit(grdrm_crtc *crtc) {

         assert(crtc->set.n_connectors > 0);

         if (pipe->base.flip)

-                slot = &pipe->base.back;

+                fb = pipe->base.back;

         else if (!crtc->applied)

-                slot = &pipe->base.front;

+                fb = pipe->base.front;

         else

                 return;

-        if (!*slot)

+        if (!fb)

                 return;

-        r = grdrm_crtc_commit_flip(crtc, slot);

+        r = grdrm_crtc_commit_flip(crtc, fb);

         if (r == 0) {

                 /* in case we couldn't page-flip, perform deep modeset */

-                grdrm_crtc_commit_deep(crtc, slot);

+                grdrm_crtc_commit_deep(crtc, fb);

         }

 }

@@ -1335,7 +1304,6 @@ static void grdrm_crtc_restore(grdrm_crtc *crtc) {

 static void grdrm_crtc_flip_complete(grdrm_crtc *crtc, uint32_t counter, struct drm_event_vblank *event) {

         bool flipped = false;

         grdrm_pipe *pipe;

-        grdrm_fb *back = NULL;

         size_t i;

         assert(crtc);

@@ -1366,15 +1334,9 @@ static void grdrm_crtc_flip_complete(grdrm_crtc *crtc, uint32_t counter, struct

                         flipped = true;

                 } else if (counter - fb->flipid < UINT16_MAX) {

                         fb->flipid = 0;

-                        back = fb;

-                } else if (fb->flipid == 0) {

-                        back = fb;

                 }

         }

-        if (!pipe->base.back && back)

-                pipe->base.back = &back->base;

-

         if (flipped) {

                 crtc->pipe->base.flipping = false;

                 grdev_pipe_frame(&pipe->base);

@@ -1561,8 +1523,32 @@ static void grdrm_pipe_free(grdev_pipe *basepipe) {

         free(pipe);

 }

+static grdev_fb *grdrm_pipe_target(grdev_pipe *basepipe) {

+        grdrm_fb *fb;

+        size_t i;

+

+        if (!basepipe->back) {

+                for (i = 0; i < basepipe->max_fbs; ++i) {

+                        if (!basepipe->fbs[i])

+                                continue;

+

+                        fb = fb_from_base(basepipe->fbs[i]);

+                        if (&fb->base == basepipe->front)

+                                continue;

+                        if (basepipe->flipping && fb->flipid)

+                                continue;

+

+                        basepipe->back = &fb->base;

+                        break;

+                }

+        }

+

+        return basepipe->back;

+}

+

 static const grdev_pipe_vtable grdrm_pipe_vtable = {

         .free                   = grdrm_pipe_free,

+        .target                 = grdrm_pipe_target,

 };

 /*

diff --git a/src/libsystemd-terminal/grdev.c b/src/libsystemd-terminal/grdev.c

index aaac06ec34..bbc45afad4 100644

--- a/src/libsystemd-terminal/grdev.c

+++ b/src/libsystemd-terminal/grdev.c

@@ -382,6 +382,8 @@ const grdev_display_target *grdev_display_next_target(grdev_display *display, co

                 if (!(fb = pipe->back)) {

                         if (!pipe->vtable->target || !(fb = pipe->vtable->target(pipe)))

                                 continue;

+

+                        assert(fb == pipe->back);

                 }

                 /* if back-buffer is up-to-date, schedule flip */