Ville Syrjälä ville.syrjala@linux.intel.com writes:
On Fri, May 11, 2018 at 09:47:49PM +0200, Boris Brezillon wrote:
On Fri, 11 May 2018 20:29:48 +0300 Ville Syrjälä ville.syrjala@linux.intel.com wrote:
On Fri, May 11, 2018 at 07:12:21PM +0200, Boris Brezillon wrote:
On Fri, 11 May 2018 19:54:02 +0300 Ville Syrjälä ville.syrjala@linux.intel.com wrote:
On Fri, May 11, 2018 at 05:52:56PM +0200, Boris Brezillon wrote:
On Fri, 11 May 2018 18:34:50 +0300 Ville Syrjälä ville.syrjala@linux.intel.com wrote:
> On Fri, May 11, 2018 at 04:59:17PM +0200, Boris Brezillon wrote: > > Applying an underscan setup is just a matter of scaling all planes > > appropriately and adjusting the CRTC X/Y offset to account for the > > horizontal and vertical border. > > > > Create an vc4_plane_underscan_adj() function doing that and call it from > > vc4_plane_setup_clipping_and_scaling() so that we are ready to attach > > underscan properties to the HDMI connector. > > > > Signed-off-by: Boris Brezillon boris.brezillon@bootlin.com > > --- > > Changes in v2: > > - Take changes on hborder/vborder meaning into account > > --- > > drivers/gpu/drm/vc4/vc4_plane.c | 49 ++++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 48 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c > > index 71d44c357d35..61ed60841cd6 100644 > > --- a/drivers/gpu/drm/vc4/vc4_plane.c > > +++ b/drivers/gpu/drm/vc4/vc4_plane.c > > @@ -258,6 +258,49 @@ static u32 vc4_get_scl_field(struct drm_plane_state *state, int plane) > > } > > } > > > > +static int vc4_plane_underscan_adj(struct drm_plane_state *pstate) > > +{ > > + struct vc4_plane_state *vc4_pstate = to_vc4_plane_state(pstate); > > + struct drm_connector_state *conn_state = NULL; > > + struct drm_connector *conn; > > + struct drm_crtc_state *crtc_state; > > + int i; > > + > > + for_each_new_connector_in_state(pstate->state, conn, conn_state, i) { > > + if (conn_state->crtc == pstate->crtc) > > + break; > > + } > > + > > + if (i == pstate->state->num_connector) > > + return 0; > > + > > + if (conn_state->underscan.mode != DRM_UNDERSCAN_ON) > > + return 0; > > + > > + crtc_state = drm_atomic_get_new_crtc_state(pstate->state, > > + pstate->crtc); > > + > > + if (conn_state->underscan.hborder >= crtc_state->mode.hdisplay || > > + conn_state->underscan.vborder >= crtc_state->mode.vdisplay) > > + return -EINVAL; > > border * 2 ?
Oops, indeed. I'll fix that.
> > > + > > + vc4_pstate->crtc_x += conn_state->underscan.hborder; > > + vc4_pstate->crtc_y += conn_state->underscan.vborder; > > + vc4_pstate->crtc_w = (vc4_pstate->crtc_w * > > + (crtc_state->mode.hdisplay - > > + (conn_state->underscan.hborder * 2))) / > > + crtc_state->mode.hdisplay; > > + vc4_pstate->crtc_h = (vc4_pstate->crtc_h * > > + (crtc_state->mode.vdisplay - > > + (conn_state->underscan.vborder * 2))) / > > + crtc_state->mode.vdisplay; > > So you're now scaling all planes? The code seems to reject scaling for > the cursor plane, how are you dealing with that? Or just no cursor > allowed when underscanning?
No, I just didn't test with a cursor plane. We should probably avoid scaling the cursor plane and just adjust its position. Eric any opinion on that?
I don't think you can just not scale it. The user asked for the cursor to be at a specific place with a specific size. Can't just ignore that and do something else. Also eg. i915 would definitely scale the cursor since we'd just scale the entire crtc instead of scaling individual planes. Different drivers doing different things wouldn't be good.
Except in our case the scaling takes place before the composition, so we don't have a choice.
The choice is to either do what userspace asked, or return an error.
Come on! If we can't use underscan when there's a cursor plane enabled this feature is pretty much useless. But let's take a real use case to show you how negligible the lack of scaling on the cursor plane will be. Say you have borders taking 10% of you screen (which is already a lot), and your cursor is a plane of 64x64 pixels, you'll end up with a 64x64 cursor instead of 58x58. Quite frankly, I doubt you'll notice the difference.
Now you're assuming the cursor is only ever used as a cursor. It can be used for other things and those may need to be positioned pixel perfect in relation to other planes/fb contents.
We used to play is fast and loose in i915 when it came to the sprite plane coordinates. People generally hated that, at least when it came to the atomic ioctl. Basically we just adjusted the src/dst coordinates until the hw was happy with them, partially ignoring what the user had asked. Maarten recently nuked that code, and so now we either respect the user's choice or we return an error.
I guess one way out of this conundrum would be to allow the cursor to violate the user's requested parameters when controlled via the legacy cursor ioctls. There are no atomicity guarantees there, so I guess we could also say there are no other correctness guarantees either. Not sure if the accuracy of the hotspot might become an issue though.
Another option might be to just scale the cursor as well. If I understand correctly the "cursor can't be scaled" limitation just comes from the fact that some vblank synced resource needs to be reconfigured whenever the scaling changes. So doing that for unthrottled cursor updates is not easy. But in this case the underscan properties are what determines the scaling so maybe that resource could be reconfigured whenever the those props change to make sure the cursor can always be scaled appropriately?
Yeah, we had no application for it, so it wasn't supported. I don't think it would be hard to have a previously-scaled cursor move, it's just that we need to fall back to a synchronous plane update if the scaling parameters change.