Re: [Nouveau] [PATCH 09/17] drm/radeon: use common fence implementation for fences

Maarten Lankhorst
2014-07-23T13:17:03Z

op 23-07-14 14:36, Christian König schreef:
> Am 23.07.2014 12:52, schrieb Daniel Vetter:
>> On Wed, Jul 23, 2014 at 12:13 PM, Christian König
>> <christian.koenig@amd.com> wrote:
>>>> And the dma-buf would still have fences belonging to both drivers, and it
>>>> would still call from outside the driver.
>>>
>>> Calling from outside the driver is fine as long as the driver can do
>>> everything necessary to complete it's work and isn't forced into any ugly
>>> hacks and things that are not 100% reliable.
>>>
>>> So I don't see much other approach as integrating recovery code for not
>>> firing interrupts and some kind of lockup handling into the fence code as
>>> well.
>> That approach doesn't really work at that well since every driver has
>> it's own reset semantics. And we're trying to move away from global
>> reset to fine-grained reset. So stop-the-world reset is out of
>> fashion, at least for i915. As you said, reset is normal in gpus and
>> we're trying to make reset less invasive. I really don't see a point
>> in imposing a reset scheme upon all drivers and I think you have about
>> as much motivation to convert radeon to the scheme used by i915 as
>> I'll have for converting to the one used by radeon. If it would fit at
>> all.
> Oh my! No, I didn't wanted to suggest any global reset infrastructure.
>
> My idea was more that the fence framework provides a fence->process_signaling callback that is periodically called after enable_signaling is called to trigger manual signal processing in the driver.
>
> This would both be suitable as a fallback in case of not working interrupts as well as a chance for any driver to do necessary lockup handling.
I managed to do it without needing it to be part of the interface? I'm not sure whether radeon_fence_driver_recheck needs exclusive_lock, but if so it's a small change..

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 7fbfd41479f1..51b646b9c8bb 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -345,6 +345,9 @@ struct radeon_fence_driver {
uint64_t sync_seq[RADEON_NUM_RINGS];
atomic64_t last_seq;
bool initialized;
+ struct delayed_work work;
+ struct radeon_device *rdev;
+ unsigned ring;
};

struct radeon_fence_cb {
diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index da83f36dd708..955c825946ad 100644
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -231,6 +231,9 @@ static bool __radeon_fence_process(struct radeon_device *rdev, int ring)
}
} while (atomic64_xchg(&rdev->fence_drv[ring].last_seq, seq) > seq);

+ if (!wake && last_seq < last_emitted)
+ schedule_delayed_work(&rdev->fence_drv[ring].work, jiffies_to_msecs(10));
+
return wake;
}

@@ -815,6 +818,14 @@ int radeon_fence_driver_start_ring(struct radeon_device *rdev, int ring)
return 0;
}

+static void radeon_fence_driver_recheck(struct work_struct *work)
+{
+ struct radeon_fence_driver *drv = container_of(work, struct radeon_fence_driver, work.work);
+
+ DRM_ERROR("omg, working!\n");
+ radeon_fence_process(drv->rdev, drv->ring);
+}
+
/**
* radeon_fence_driver_init_ring - init the fence driver
* for the requested ring.
@@ -836,6 +847,10 @@ static void radeon_fence_driver_init_ring(struct radeon_device *rdev, int ring)
rdev->fence_drv[ring].sync_seq[i] = 0;
atomic64_set(&rdev->fence_drv[ring].last_seq, 0);
rdev->fence_drv[ring].initialized = false;
+
+ rdev->fence_drv[ring].ring = ring;
+ rdev->fence_drv[ring].rdev = rdev;
+ INIT_DELAYED_WORK(&rdev->fence_drv[ring].work, radeon_fence_driver_recheck);
}

/**
@@ -880,6 +895,7 @@ void radeon_fence_driver_fini(struct radeon_device *rdev)
for (ring = 0; ring < RADEON_NUM_RINGS; ring++) {
if (!rdev->fence_drv[ring].initialized)
continue;
+ cancel_delayed_work_sync(&rdev->fence_drv[ring].work);
r = radeon_fence_wait_empty(rdev, ring);
if (r) {
/* no need to trigger GPU reset as we are unloading */
diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c
index 16807afab362..85391ddd3ce9 100644
--- a/drivers/gpu/drm/radeon/radeon_irq_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c
@@ -331,7 +331,7 @@ void radeon_irq_kms_sw_irq_get(struct radeon_device *rdev, int ring)
{
unsigned long irqflags;

- if (!rdev->ddev->irq_enabled)
+// if (!rdev->ddev->irq_enabled)
return;

if (atomic_inc_return(&rdev->irq.ring_int[ring]) == 1) {
@@ -355,7 +355,7 @@ void radeon_irq_kms_sw_irq_put(struct radeon_device *rdev, int ring)
{
unsigned long irqflags;

- if (!rdev->ddev->irq_enabled)
+// if (!rdev->ddev->irq_enabled)
return;

if (atomic_dec_and_test(&rdev->irq.ring_int[ring])) {