drm/nv50-/mc: fix kms pageflip events by reordering irq handling order.

Whenever a single nouveau_mc_intr() main gpu irq-handler invocation was
responsible for calling both, the vblank-irq handler (display engine irq)
and kms-pageflip completion handler (from fifo irq), the order of
invocation was wrong. nouveau_finish_flip() was called before
drm_handle_vblank() for the vblank of pageflip completion, so the
emitted pageflip event contained stale vblank count and timestamp
from previous vblank. This caused failure in userspace to timestamp
properly.

Reorder order of invocation of engine irq handlers: Put
NVDEV_ENGINE_DISP always on top, and thereby before NVDEV_ENGINE_FIFO,
so that drm_handle_vblank() gets called to update vblank timestamps
and count before potential pageflip events make use of that
information.

This works on nv-50 and later, where kms-pageflip completion triggers
an irq either after a separate vblank irq, or both pageflip and vblank
trigger one common irq invocation, but never before vblank irqs.

v2 (Ben):
- removed mods for nv04-nv40, it doesn't help there anyway
- this is considered a hack, and a better solution should be found

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: <stable@vger.kernel.org> # 3.13+

diff --git a/drivers/gpu/drm/nouveau/core/subdev/mc/nv50.c b/drivers/gpu/drm/nouveau/core/subdev/mc/nv50.c
index e8822a934c485742f9b2e8452225ec93ddec5f07..90d8bf8ce0dc5039735f46953e0ac0e134de8869 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/subdev/mc/nv50.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/mc/nv50.c
@@ -26,6 +26,7 @@
 
 const struct nouveau_mc_intr
 nv50_mc_intr[] = {
+       { 0x04000000, NVDEV_ENGINE_DISP },  /* DISP before FIFO, so pageflip-timestamping works! */
        { 0x00000001, NVDEV_ENGINE_MPEG },
        { 0x00000100, NVDEV_ENGINE_FIFO },
        { 0x00001000, NVDEV_ENGINE_GR },
@@ -34,7 +35,6 @@ nv50_mc_intr[] = {
        { 0x00020000, NVDEV_ENGINE_VP },        /* NV84- */
        { 0x00100000, NVDEV_SUBDEV_TIMER },
        { 0x00200000, NVDEV_SUBDEV_GPIO },
-       { 0x04000000, NVDEV_ENGINE_DISP },
        { 0x10000000, NVDEV_SUBDEV_BUS },
        { 0x80000000, NVDEV_ENGINE_SW },
        { 0x0002d101, NVDEV_SUBDEV_FB },

diff --git a/drivers/gpu/drm/nouveau/core/subdev/mc/nv98.c b/drivers/gpu/drm/nouveau/core/subdev/mc/nv98.c
index f8a6f18e2d3408f55b1447e55144e24ded4036f9..95b3d35388a86ee71d893d01b539f4087f1dd9e5 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/subdev/mc/nv98.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/mc/nv98.c
@@ -26,6 +26,7 @@
 
 static const struct nouveau_mc_intr
 nv98_mc_intr[] = {
+       { 0x04000000, NVDEV_ENGINE_DISP },  /* DISP first, so pageflip timestamps work */
        { 0x00000001, NVDEV_ENGINE_PPP },
        { 0x00000100, NVDEV_ENGINE_FIFO },
        { 0x00001000, NVDEV_ENGINE_GR },
@@ -37,7 +38,6 @@ nv98_mc_intr[] = {
        { 0x00100000, NVDEV_SUBDEV_TIMER },
        { 0x00200000, NVDEV_SUBDEV_GPIO },
        { 0x00400000, NVDEV_ENGINE_COPY0 },     /* NVA3-     */
-       { 0x04000000, NVDEV_ENGINE_DISP },
        { 0x10000000, NVDEV_SUBDEV_BUS },
        { 0x80000000, NVDEV_ENGINE_SW },
        { 0x0042d101, NVDEV_SUBDEV_FB },

diff --git a/drivers/gpu/drm/nouveau/core/subdev/mc/nvc0.c b/drivers/gpu/drm/nouveau/core/subdev/mc/nvc0.c
index 34472d3170974ca8e6207afe0a347f332130d6bd..ac7f99a15fa7b530e47316919a2aee655817f5a3 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/subdev/mc/nvc0.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/mc/nvc0.c
@@ -26,6 +26,7 @@
 
 const struct nouveau_mc_intr
 nvc0_mc_intr[] = {
+       { 0x04000000, NVDEV_ENGINE_DISP },  /* DISP first, so pageflip timestamps work. */
        { 0x00000001, NVDEV_ENGINE_PPP },
        { 0x00000020, NVDEV_ENGINE_COPY0 },
        { 0x00000040, NVDEV_ENGINE_COPY1 },
@@ -40,7 +41,6 @@ nvc0_mc_intr[] = {
        { 0x00200000, NVDEV_SUBDEV_GPIO },
        { 0x01000000, NVDEV_SUBDEV_PWR },
        { 0x02000000, NVDEV_SUBDEV_LTCG },
-       { 0x04000000, NVDEV_ENGINE_DISP },
        { 0x08000000, NVDEV_SUBDEV_FB },
        { 0x10000000, NVDEV_SUBDEV_BUS },
        { 0x40000000, NVDEV_SUBDEV_IBUS },