[PATCH] drm/amd/amdgpu: Correct ring wptr address in debugfs

[Tom St Denis]

On 29/03/17 01:46 PM, Christian König wrote:
> Am 29.03.2017 um 19:44 schrieb Tom St Denis:
>> On 29/03/17 01:41 PM, Christian König wrote:
>>> Am 29.03.2017 um 19:07 schrieb Tom St Denis:
>>>> On 29/03/17 01:07 PM, Tom St Denis wrote:
>>>>> On gfx9 hardware the value is not wrapped and is a 64-bit value.  So
>>>>> we reduce it modulo the ring size.
>>>>>
>>>>> Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
>>>>> ---
>>>>>  drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 4 ++--
>>>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>>>>> index ac0ce3f27f87..b6d2c0b2a501 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>>>>> @@ -320,8 +320,8 @@ static ssize_t amdgpu_debugfs_ring_read(struct
>>>>> file *f, char __user *buf,
>>>>>
>>>>>      if (*pos < 12) {
>>>>>          early[0] = amdgpu_ring_get_rptr(ring);
>>>>> -        early[1] = amdgpu_ring_get_wptr(ring);
>>>>> -        early[2] = ring->wptr;
>>>>> +        early[1] = amdgpu_ring_get_wptr(ring) & ((ring->ring_size >>
>>>>> 2) - 1);
>>>>> +        early[2] = ring->wptr & ((ring->ring_size >> 2) - 1);
>>>>>          for (i = *pos / 4; i < 3 && size; i++) {
>>>>>              r = put_user(early[i], (uint32_t *)buf);
>>>>>              if (r)
>>>>>
>>>>
>>>> Particularly if reviewers could make sure I got the dword/byte
>>>> conversion correct here.  It's my understanding ring_size is bytes and
>>>> the get_*ptr() macros is in dwords right?
>>>
>>> Actually you should use ptr_mask here instead, this way you don't need
>>> to mess with the ring size at all.
>>
>>     ring->buf_mask = (ring->ring_size / 4) - 1;
>>     ring->ptr_mask = ring->funcs->support_64bit_ptrs ?
>>         0xffffffffffffffff : ring->buf_mask;
>>
>> This won't wrap the value like debugfs needs though.
>
> Ups, I meant buf_mask instead of ptr_mask.
>
> We seem to mess those two up more than once, might think about a better
> name for them.
>

Righto v2 coming up.

Cheers,
Tom