[PATCH AUTOSEL 5.7 16/60] drm/nouveau/kms/nv50-: Fix disabling dithering

Sasha Levin
2020-08-10T19:10:54Z

From: Lyude Paul <lyude@redhat.com>

[ Upstream commit fb2420b701edbf96c2b6d557f0139902f455dc2b ]

While we expose the ability to turn off hardware dithering for nouveau,
we actually make the mistake of turning it on anyway, due to
dithering_depth containing a non-zero value if our dithering depth isn't
also set to 6 bpc.

So, fix it by never enabling dithering when it's disabled.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200627194657.156514-6-lyude@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/nouveau/dispnv50/head.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/head.c b/drivers/gpu/drm/nouveau/dispnv50/head.c
index 8f6455697ba72..ed6819519f6d8 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/head.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/head.c
@@ -84,18 +84,20 @@ nv50_head_atomic_check_dither(struct nv50_head_atom *armh,
{
u32 mode = 0x00;

- if (asyc->dither.mode == DITHERING_MODE_AUTO) {
- if (asyh->base.depth > asyh->or.bpc * 3)
- mode = DITHERING_MODE_DYNAMIC2X2;
- } else {
- mode = asyc->dither.mode;
- }
+ if (asyc->dither.mode) {
+ if (asyc->dither.mode == DITHERING_MODE_AUTO) {
+ if (asyh->base.depth > asyh->or.bpc * 3)
+ mode = DITHERING_MODE_DYNAMIC2X2;
+ } else {
+ mode = asyc->dither.mode;
+ }

- if (asyc->dither.depth == DITHERING_DEPTH_AUTO) {
- if (asyh->or.bpc >= 8)
- mode |= DITHERING_DEPTH_8BPC;
- } else {
- mode |= asyc->dither.depth;
+ if (asyc->dither.depth == DITHERING_DEPTH_AUTO) {
+ if (asyh->or.bpc >= 8)
+ mode |= DITHERING_DEPTH_8BPC;
+ } else {
+ mode |= asyc->dither.depth;
+ }
}

asyh->dither.enable = mode;
--
2.25.1