True indeed. Something like 256 + 32 * num_ibs (or even 16 * num_ibs???
Need to double check) should do as well.
Christian.
Am 25.08.2016 um 10:28 schrieb Liu, Monk:
But even user space will submit 10 ibs this submission, the calculate of
256*ibs is totally overflow, remember that ring buffer is only 4kb size
-----Original Message-----
From: Christian König [mailto:deathsim...@vodafone.de]
Sent: Thursday, August 25, 2016 4:12 PM
To: Liu, Monk <monk....@amd.com>; amd-gfx@lists.freedesktop.org
Subject: Re: [PATCH 2/2] drm/amdgpu:256dw is enough for one ib_schedule
Well userspace is allowed to send any number of IBs down to this if I remember
correctly.
So we clearly need something depending on the number of IBs or reject
submissions with to many IBs earlier in the CS.
Otherwise we clearly open up a possible problem where userspace can trigger a
ring overrun.
Regards,
Christian.
Am 25.08.2016 um 07:58 schrieb Monk Liu:
Change-Id: I1ee3258276868a753e536ae2d9ae1b12e7eaf791
Signed-off-by: Monk Liu <monk....@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
index 4e5b2f3..b82904c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
@@ -151,7 +151,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned
num_ibs,
return -EINVAL;
}
- r = amdgpu_ring_alloc(ring, 256 * num_ibs);
+ r = amdgpu_ring_alloc(ring, 256);
if (r) {
dev_err(adev->dev, "scheduling IB failed (%d).\n", r);
return r;
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