Hi Tvrtko,
On 18/12/24 07:41, Tvrtko Ursulin wrote:
On 12/12/2024 20:20, Maíra Canal wrote:
As the BOs used by VC4 have DMA Reservation Objects attached to it,
there is no need to use seqnos wait for the BOs availability. Instead,
we can use `dma_gem_dma_resv_wait()`.
Signed-off-by: Maíra Canal <mcanal@xxxxxxxxxx>
---
drivers/gpu/drm/vc4/vc4_drv.h | 10 ++++++++++
drivers/gpu/drm/vc4/vc4_gem.c | 31 +++++++++++++++++++------------
2 files changed, 29 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/
vc4_drv.h
index 4a078ffd9f82..03ed40ab9a93 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -924,6 +924,16 @@ struct vc4_validated_shader_info {
(Wmax))
#define wait_for(COND, MS) _wait_for((COND), (MS) * 1000, 10,
1000)
+static inline unsigned long nsecs_to_jiffies_timeout(const u64 n)
+{
+ /* nsecs_to_jiffies64() does not guard against overflow */
+ if ((NSEC_PER_SEC % HZ) != 0 &&
+ div_u64(n, NSEC_PER_SEC) >= MAX_JIFFY_OFFSET / HZ)
+ return MAX_JIFFY_OFFSET;
+
+ return min_t(u64, MAX_JIFFY_OFFSET, nsecs_to_jiffies64(n) + 1);
+}
+
/* vc4_bo.c */
struct drm_gem_object *vc4_create_object(struct drm_device *dev,
size_t size);
struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t size,
diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/
vc4_gem.c
index 1021f45cb53c..4037c65eb269 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -1017,11 +1017,13 @@ int
vc4_wait_bo_ioctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
- struct vc4_dev *vc4 = to_vc4_dev(dev);
int ret;
+ struct vc4_dev *vc4 = to_vc4_dev(dev);
struct drm_vc4_wait_bo *args = data;
- struct drm_gem_object *gem_obj;
- struct vc4_bo *bo;
+ unsigned long timeout_jiffies =
+ nsecs_to_jiffies_timeout(args->timeout_ns);
What about a potentially simpler alternative:
timeout_jiffies = usecs_to_jiffies(div_u64(args->timeout_ns, 1000));
No need for a new helper and code cannot sleep for less than one jiffy
anyway.
I ended up deciding to use a function available on "drm_utils.h",
`drm_timeout_abs_to_jiffies()`, which seems to deal appropriately with
overflows.
+ ktime_t start = ktime_get();
+ u64 delta_ns;
if (WARN_ON_ONCE(vc4->gen > VC4_GEN_4))
return -ENODEV;
@@ -1029,17 +1031,22 @@ vc4_wait_bo_ioctl(struct drm_device *dev, void
*data,
if (args->pad != 0)
return -EINVAL;
- gem_obj = drm_gem_object_lookup(file_priv, args->handle);
- if (!gem_obj) {
- DRM_DEBUG("Failed to look up GEM BO %d\n", args->handle);
- return -EINVAL;
- }
- bo = to_vc4_bo(gem_obj);
+ ret = drm_gem_dma_resv_wait(file_priv, args->handle,
+ true, timeout_jiffies);
- ret = vc4_wait_for_seqno_ioctl_helper(dev, bo->seqno,
- &args->timeout_ns);
+ /* Decrement the user's timeout, in case we got interrupted
+ * such that the ioctl will be restarted.
+ */
+ delta_ns = ktime_to_ns(ktime_sub(ktime_get(), start));
+ if (delta_ns < args->timeout_ns)
+ args->timeout_ns -= delta_ns;
+ else
+ args->timeout_ns = 0;
+
+ /* Asked to wait beyond the jiffy/scheduler precision? */
+ if (ret == -ETIME && args->timeout_ns)
+ ret = -EAGAIN;
EAGAIN is new from here, right? Will userspace cope in the right way?
Thanks for noticing! I'll address it in the next version.
Best Regards,
- Maíra
Regards,
Tvrtko
- drm_gem_object_put(gem_obj);
return ret;
}
