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drm/nouveau/disp/nv50-: fix center/aspect-corrected scaling

Previously center scaling would get scaling applied to it (when it was
only supposed to center the image), and aspect-corrected scaling did not
always correctly pick whether to reduce width or height for a particular
combination of inputs/outputs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110660
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
alistair/sunxi64-5.4-dsi
Ilia Mirkin 2019-05-25 18:41:49 -04:00 committed by Ben Skeggs
parent f8d6211ac7
commit 533f475240
1 changed files with 24 additions and 4 deletions

View File

@ -169,14 +169,34 @@ nv50_head_atomic_check_view(struct nv50_head_atom *armh,
*/
switch (mode) {
case DRM_MODE_SCALE_CENTER:
asyh->view.oW = min((u16)umode->hdisplay, asyh->view.oW);
asyh->view.oH = min((u16)umode_vdisplay, asyh->view.oH);
/* fall-through */
/* NOTE: This will cause scaling when the input is
* larger than the output.
*/
asyh->view.oW = min(asyh->view.iW, asyh->view.oW);
asyh->view.oH = min(asyh->view.iH, asyh->view.oH);
break;
case DRM_MODE_SCALE_ASPECT:
if (asyh->view.oH < asyh->view.oW) {
/* Determine whether the scaling should be on width or on
* height. This is done by comparing the aspect ratios of the
* sizes. If the output AR is larger than input AR, that means
* we want to change the width (letterboxed on the
* left/right), otherwise on the height (letterboxed on the
* top/bottom).
*
* E.g. 4:3 (1.333) AR image displayed on a 16:10 (1.6) AR
* screen will have letterboxes on the left/right. However a
* 16:9 (1.777) AR image on that same screen will have
* letterboxes on the top/bottom.
*
* inputAR = iW / iH; outputAR = oW / oH
* outputAR > inputAR is equivalent to oW * iH > iW * oH
*/
if (asyh->view.oW * asyh->view.iH > asyh->view.iW * asyh->view.oH) {
/* Recompute output width, i.e. left/right letterbox */
u32 r = (asyh->view.iW << 19) / asyh->view.iH;
asyh->view.oW = ((asyh->view.oH * r) + (r / 2)) >> 19;
} else {
/* Recompute output height, i.e. top/bottom letterbox */
u32 r = (asyh->view.iH << 19) / asyh->view.iW;
asyh->view.oH = ((asyh->view.oW * r) + (r / 2)) >> 19;
}