The i2c bus can be both accessed by DRM itself, along with any of it's
devnodes (/sys/class/i2c). So, we need to make sure that all codepaths
using the i2c bus keep the GPU resumed.

Signed-off-by: Lyude Paul <ly...@redhat.com>
Cc: Karol Herbst <karolher...@gmail.com>
Cc: sta...@vger.kernel.org
---
 drivers/gpu/drm/nouveau/nvkm/subdev/i2c/bus.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/bus.c 
b/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/bus.c
index 807a2b67bd64..1de48c990b80 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/bus.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/i2c/bus.c
@@ -119,18 +119,28 @@ nvkm_i2c_bus_release(struct nvkm_i2c_bus *bus)
        BUS_TRACE(bus, "release");
        nvkm_i2c_pad_release(pad);
        mutex_unlock(&bus->mutex);
+       pm_runtime_put_autosuspend(pad->i2c->subdev.device->dev);
 }
 
 int
 nvkm_i2c_bus_acquire(struct nvkm_i2c_bus *bus)
 {
        struct nvkm_i2c_pad *pad = bus->pad;
+       struct device *dev = pad->i2c->subdev.device->dev;
        int ret;
+
        BUS_TRACE(bus, "acquire");
+
+       ret = pm_runtime_get_sync(dev);
+       if (ret < 0 && ret != -EACCES)
+               return ret;
+
        mutex_lock(&bus->mutex);
        ret = nvkm_i2c_pad_acquire(pad, NVKM_I2C_PAD_I2C);
-       if (ret)
+       if (ret) {
                mutex_unlock(&bus->mutex);
+               pm_runtime_put_autosuspend(dev);
+       }
        return ret;
 }
 
-- 
2.17.1

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