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drm/nouveau/pmu: be more strict about locking 

When we start communicating with the pmu a bit more, the current code is
a real issue. I encountered a dead lock here, while testing my dynamic
reclocking code

Signed-off-by: Karol Herbst <nouveau@karolherbst.de>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This commit is contained in:
Karol Herbst 2016-01-11 02:58:03 +01:00 committed by Ben Skeggs
parent c6007dc4e5
commit 7d28dbae22
1 changed files with 5 additions and 3 deletions
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8
drivers/gpu/drm/nouveau/nvkm/subdev/pmu/base.c
View File

@ -40,21 +40,23 @@ nvkm_pmu_send(struct nvkm_pmu *pmu, u32 reply[2],
struct nvkm_device *device = subdev->device; struct nvkm_device *device = subdev->device;
u32 addr; u32 addr;
mutex_lock(&subdev->mutex);
/* wait for a free slot in the fifo */ /* wait for a free slot in the fifo */
addr = nvkm_rd32(device, 0x10a4a0); addr = nvkm_rd32(device, 0x10a4a0);
if (nvkm_msec(device, 2000, if (nvkm_msec(device, 2000,
u32 tmp = nvkm_rd32(device, 0x10a4b0); u32 tmp = nvkm_rd32(device, 0x10a4b0);
if (tmp != (addr ^ 8)) if (tmp != (addr ^ 8))
break; break;
) < 0) ) < 0) {
mutex_unlock(&subdev->mutex);
return -EBUSY; return -EBUSY;
}
/* we currently only support a single process at a time waiting /* we currently only support a single process at a time waiting
* on a synchronous reply, take the PMU mutex and tell the * on a synchronous reply, take the PMU mutex and tell the
* receive handler what we're waiting for * receive handler what we're waiting for
*/ */
if (reply) { if (reply) {
mutex_lock(&subdev->mutex);
pmu->recv.message = message; pmu->recv.message = message;
pmu->recv.process = process; pmu->recv.process = process;
} }
@ -81,9 +83,9 @@ nvkm_pmu_send(struct nvkm_pmu *pmu, u32 reply[2],
wait_event(pmu->recv.wait, (pmu->recv.process == 0)); wait_event(pmu->recv.wait, (pmu->recv.process == 0));
reply[0] = pmu->recv.data[0]; reply[0] = pmu->recv.data[0];
reply[1] = pmu->recv.data[1]; reply[1] = pmu->recv.data[1];
mutex_unlock(&subdev->mutex);
} }
mutex_unlock(&subdev->mutex);
return 0; return 0;
} }