Since upgrading to linux-next based on 5.9.0-rc1 and 5.9.0-rc2 I have had my mouse pointer disappear soon after logging in, and I have observed the system freezing temporarily when clicking on objects and when typing text. I have also found records of push buffer errors in dmesg output: [ 6625.450394] nouveau 0000:01:00.0: disp: ERROR 1 [PUSHBUFFER_ERR] 02 [] chid 0 mthd 0000 data 00000400 I tried setting CONFIG_NOUVEAU_DEBUG=5 (tracing) to try and collect further debug info, but nothing caught the eye. The error message in question comes from nv50_disp_intr_error in drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c:613,645. And nv50_disp_intr_error is called from nv50_disp_intr in the following while block: drivers/gpu/drm/nouveau/nvkm/engine/disp/nv50.c:647,658 void nv50_disp_intr(struct nv50_disp *disp) { struct nvkm_device *device = disp->base.engine.subdev.device; u32 intr0 = nvkm_rd32(device, 0x610020); u32 intr1 = nvkm_rd32(device, 0x610024); while (intr0 & 0x001f0000) { u32 chid = __ffs(intr0 & 0x001f0000) - 16; nv50_disp_intr_error(disp, chid); intr0 &= ~(0x00010000 << chid); } ... } Could this be in any way related to this series of commits? commit 0a96099691c8cd1ac0744ef30b6846869dc2b566 Author: Ben Skeggs <bskeggs@xxxxxxxxxx> Date: Tue Jul 21 11:34:07 2020 +1000 drm/nouveau/kms/nv50-: implement proper push buffer control logic We had a, what was supposed to be temporary, hack in the KMS code where we'd completely drain an EVO/NVD channel's push buffer when wrapping to the start again, instead of treating it as a ring buffer. Let's fix that, finally. Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx> Here are my GPU details: 01:00.0 VGA compatible controller: NVIDIA Corporation GT216 [GeForce 210] (rev a1) Subsystem: Micro-Star International Co., Ltd. [MSI] Device 8a93 Kernel driver in use: nouveau The last linux-next kernel I built where the problem reported does not manifest itself is 5.8.0-rc6-next-20200720. I would appreciate being given any pointers on how to further debug this. Or is git bisect the only way to proceed with this? Thanks.