From: Ben Skeggs bskeggs@redhat.com
[ Upstream commit 028a12f5aa829b4ba6ac011530b815eda4960e89 ]
Certain boards with GP107/GP108 chipsets hang (often, but randomly) for unknown reasons during GR initialisation.
The first tell-tale symptom of this issue is:
nouveau 0000:01:00.0: bus: MMIO read of 00000000 FAULT at 409800 [ TIMEOUT ]
appearing in dmesg, likely followed by many other failures being logged.
Karol found this WAR for the issue a while back, but efforts to isolate the root cause and proper fix have not yielded success so far. I've modified the original patch to include a few more details, limit it to GP107/GP108 by default, and added a config option to override this choice.
Signed-off-by: Ben Skeggs bskeggs@redhat.com Reviewed-by: Karol Herbst kherbst@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../gpu/drm/nouveau/nvkm/engine/gr/gf100.c | 26 +++++++++++++++++++ 1 file changed, 26 insertions(+)
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c b/drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c index c578deb5867a8..c71606a45d1de 100644 --- a/drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c +++ b/drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c @@ -1988,8 +1988,34 @@ gf100_gr_init_(struct nvkm_gr *base) { struct gf100_gr *gr = gf100_gr(base); struct nvkm_subdev *subdev = &base->engine.subdev; + struct nvkm_device *device = subdev->device; + bool reset = device->chipset == 0x137 || device->chipset == 0x138; u32 ret;
+ /* On certain GP107/GP108 boards, we trigger a weird issue where + * GR will stop responding to PRI accesses after we've asked the + * SEC2 RTOS to boot the GR falcons. This happens with far more + * frequency when cold-booting a board (ie. returning from D3). + * + * The root cause for this is not known and has proven difficult + * to isolate, with many avenues being dead-ends. + * + * A workaround was discovered by Karol, whereby putting GR into + * reset for an extended period right before initialisation + * prevents the problem from occuring. + * + * XXX: As RM does not require any such workaround, this is more + * of a hack than a true fix. + */ + reset = nvkm_boolopt(device->cfgopt, "NvGrResetWar", reset); + if (reset) { + nvkm_mask(device, 0x000200, 0x00001000, 0x00000000); + nvkm_rd32(device, 0x000200); + msleep(50); + nvkm_mask(device, 0x000200, 0x00001000, 0x00001000); + nvkm_rd32(device, 0x000200); + } + nvkm_pmu_pgob(gr->base.engine.subdev.device->pmu, false);
ret = nvkm_falcon_get(gr->fecs.falcon, subdev);