drm/nouveau/disp/r535: Add scanline position support + head state support

That's right! It looks like this never actually got finished, something which I just noticed today when I saw this fun message spamming one of my test machine's kernel logs when enabling display debug output for nouveau:

[drm:drm_crtc_vblank_helper_get_vblank_timestamp_internal] crtc 0 : scanoutpos query failed.

So it looks like we've been falling back to DRM's core fallback for a while now, whoops.

So, while it seems that we do have the option of doing this through GSP - that doesn't seem like a great idea. Mainly because reading this from GSP would involve a lot more latency then we should have for vblank handling due to the RPC communication. So instead of implementing that, just use gv100_head_state and gv100_head_rgpos for implementing .state and .rgpos. It seems to work perfectly fine!

Fixes 9e9944449023 ("drm/nouveau/disp/r535: initial support")

Cc Ben Skeggs <[email protected]>

Cc Dave Airlie <[email protected]>

Cc Timur Tabi <[email protected]>

Cc Ben Skeggs <[email protected]>

Cc James Jones <[email protected]>

Cc Faith Ekstrand <[email protected]>

Cc Suraj Kandpal <[email protected]>

Cc Lyude Paul <[email protected]>

Cc Aaron Kling <[email protected]>

Cc Danilo Krummrich <[email protected]>

Cc Zhang Enpei <[email protected]>

Cc <[email protected]> # v6.7+

Signed-off-by Lyude Paul <[email protected]>

---
 drivers/gpu/drm/nouveau/nvkm/engine/disp/gv100.c       | 4 ++--
 drivers/gpu/drm/nouveau/nvkm/engine/disp/head.h        | 2 ++
 drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/disp.c | 8 ++------
 3 files changed, 6 insertions(+), 8 deletions(-)

drivers/gpu/drm/nouveau/nvkm/engine/disp/gv100.c +2 -2

index dbd984da75014..0608266188d3e 100644
@@ -253,7 +253,7 @@ gv100_head_vblank_get(struct nvkm_head *head)
        nvkm_mask(device, 0x611d80 + (head->id * 4), 0x00000004, 0x00000004);
 }
 
-static void
+void
 gv100_head_rgpos(struct nvkm_head *head, u16 *hline, u16 *vline)
 {
        struct nvkm_device *device = head->disp->engine.subdev.device;

@@ -263,7 +263,7 @@ gv100_head_rgpos(struct nvkm_head *head, u16 *hline, u16 *vline)
        *hline = nvkm_rd32(device, 0x616334 + hoff) & 0x0000ffff;
 }
 
-static void
+void
 gv100_head_state(struct nvkm_head *head, struct nvkm_head_state *state)
 {
        struct nvkm_device *device = head->disp->engine.subdev.device;

drivers/gpu/drm/nouveau/nvkm/engine/disp/head.h +2 -0

index 856252bf559a4..b642729c254fe 100644
@@ -53,6 +53,8 @@ void gf119_head_rgclk(struct nvkm_head *, int);
 
 int gv100_head_cnt(struct nvkm_disp *, unsigned long *);
 int gv100_head_new(struct nvkm_disp *, int id);
+void gv100_head_state(struct nvkm_head *head, struct nvkm_head_state *state);
+void gv100_head_rgpos(struct nvkm_head *head, u16 *hline, u16 *vline);
 
 #define HEAD_MSG(h,l,f,a...) do {                                              \
        struct nvkm_head *_h = (h);                                            \

drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/disp.c +2 -6

index 6e63df816d855..49a1eef9bdf14 100644
@@ -625,14 +625,10 @@ r535_head_vblank_get(struct nvkm_head *head)
        nvkm_mask(device, 0x611d80 + (head->id * 4), 0x00000002, 0x00000002);
 }
 
-static void
-r535_head_state(struct nvkm_head *head, struct nvkm_head_state *state)
-{
-}
-
 static const struct nvkm_head_func
 r535_head = {
-       .state = r535_head_state,
+       .state = gv100_head_state,
+       .rgpos = gv100_head_rgpos,
        .vblank_get = r535_head_vblank_get,
        .vblank_put = r535_head_vblank_put,
 };

base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731 --
2.54.0