From ca386aa7155a5467fa7b2b8376f4da8f8e59be4d Mon Sep 17 00:00:00 2001 From: Ben Skeggs Date: Wed, 2 Sep 2020 15:30:33 +1000 Subject: drm/nouveau/kms/nv50-gp1xx: add WAR for EVO push buffer HW bug Thanks to NVIDIA for confirming this workaround, and clarifying which HW is affected. Signed-off-by: Ben Skeggs Tested-by: Alexander Kapshuk --- drivers/gpu/drm/nouveau/dispnv50/disp.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c index e7874877da85..1ed242070001 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c @@ -257,6 +257,12 @@ nv50_dmac_create(struct nvif_device *device, struct nvif_object *disp, dmac->push->end = dmac->push->bgn; dmac->max = 0x1000/4 - 1; + /* EVO channels are affected by a HW bug where the last 12 DWORDs + * of the push buffer aren't able to be used safely. + */ + if (disp->oclass < GV100_DISP) + dmac->max -= 12; + args->pushbuf = nvif_handle(&dmac->_push.mem.object); ret = nv50_chan_create(device, disp, oclass, head, data, size, -- cgit v1.2.3