Am 25.05.2018 um 17:33 schrieb Boyuan Zhang:
>
>
> On 2018-05-25 05:07 AM, Christian König wrote:
>> Am 24.05.2018 um 22:15 schrieb boyuan.zhang at amd.com:
>>> From: Boyuan Zhang <boyuan.zhang at amd.com>
>>>
>>> Allocate extra space in vcn jpeg ring buffer and store the jpeg ring
>>> patch
>>>
>>> Signed-off-by: Boyuan Zhang <boyuan.zhang at amd.com>
>>> ---
>>> Â drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c | 27
>>> ++++++++++++++++++++++++++-
>>> Â 1 file changed, 26 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c
>>> b/drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c
>>> index dcd1a9a..2e4bd26 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c
>>> @@ -119,7 +119,8 @@ static int vcn_v1_0_sw_init(void *handle)
>>> Â Â Â Â Â Â ring = &adev->vcn.ring_jpeg;
>>> Â Â Â Â Â sprintf(ring->name, "vcn_jpeg");
>>> -Â Â Â r = amdgpu_ring_init(adev, ring, 512, &adev->vcn.irq, 0);
>>> +Â Â Â /* allocate extra dw in ring buffer for storing patch commands */
>>> +Â Â Â r = amdgpu_ring_init(adev, ring, 512 + 64, &adev->vcn.irq, 0);
Taking a closer look that hack might not work after all. E.g. you need
to overwrite max_dw, buf_mask and ptr_mask after initialization.
Maybe add an "extra_dw" field into amdgpu_ring_funcs and use that in
amdgpu_ring_init().
>>> Â Â Â Â Â if (r)
>>> Â Â Â Â Â Â Â Â Â return r;
>>> Â @@ -679,6 +680,30 @@ static int vcn_v1_0_start(struct
>>> amdgpu_device *adev)
>>> Â Â Â Â Â WREG32_SOC15(UVD, 0, mmUVD_JRBC_RB_WPTR, 0);
>>> Â Â Â Â Â WREG32_SOC15(UVD, 0, mmUVD_JRBC_RB_CNTL, 0x00000002L);
>>> Â +Â Â Â /* set wptr to the extra allocated space in ring buffer */
>>> +Â Â Â ring->wptr = RREG32_SOC15(UVD, 0, mmUVD_JRBC_RB_WPTR);
>>> +Â Â Â ring->wptr += ring->max_dw * amdgpu_sched_hw_submission;
>>> +
>>> +Â Â Â /* increase mask to allow to write to the extra space */
>>> +Â Â Â ring->buf_mask += 64 * 4;
>>> +Â Â Â ring->ptr_mask += 64 * 4;
>>
>> Well that is rather ugly. buf_mask and ptr_mask are bit masks, you
>> could set them to 0xffffffff but what you do here might not work as
>> expected.
>
> OK, so maybe setting both mask to 0xffffffff temporarily to allow
> writing to extra space as mu as needed, then later on set them back?
Yeah, that should at least work as expected. I would also add a comment
here why we actually do all this.
>
>>
>>> +
>>> +Â Â Â /* allocate extra space */
>>> +Â Â Â r = amdgpu_ring_alloc(ring, 64);
>>> +Â Â Â if (r) {
>>> +Â Â Â Â Â Â Â DRM_ERROR("amdgpu: cp failed to lock ring %d (%d).\n",
>>> +Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â ring->idx, r);
>>> +Â Â Â Â Â Â Â return r;
>>> +Â Â Â }
Would be nice if we could avoid that call as well, cause this is really
not ring buffer operation but rather setting up the environment.
>>> +
>>> +Â Â Â /* copy patch commands to the extra space */
>>> +Â Â Â vcn_v1_0_jpeg_ring_set_patch_ring(ring);
>>
>> Can't vcn_v1_0_jpeg_ring_set_patch_ring() just patch the command
>> directly to he end of the ring buffer?
>>
>> In other words why do we need to use amdgpu_ring_write() in
>> vcn_v1_0_jpeg_ring_set_patch_ring()?
>>
>> Christian.
>
> Could you give me some more detailed info on how to do that? I thought
> amdgpu_ring_write() is the best way to write commands to the ring,
> what is the other/better way to do it in this case? Could you point me
> to a simple example how to write command directly to the end of ring
> (without ring_write)?
Well something like this should work:
/* pointer to the end of the ring buffer */
i = ring->max_dw * amdgpu_sched_hw_submission;
ring->ring[i++] = ....
ring->ring[i++] = ....
ring->ring[i++] = ....
ring->ring[i++] = ....
Regards,
Christian.
>
> Thanks,
> Boyuan
>
>>
>>> +
>>> +Â Â Â /* reset wptr and mask */
>>> +Â Â Â ring->wptr = RREG32_SOC15(UVD, 0, mmUVD_JRBC_RB_WPTR);
>>> +Â Â Â ring->buf_mask -= 0x100;
>>> +Â Â Â ring->ptr_mask -= 0x100;
>>> +
>>> Â Â Â Â Â return 0;
>>> Â }
>>
>
