On Tue, Jul 17, 2012 at 5:59 AM, Christian König
<deathsimple@xxxxxxxxxxx> wrote:
> On 16.07.2012 23:14, alexdeucher@xxxxxxxxx wrote:
>>
>> From: Alex Deucher <alexander.deucher@xxxxxxx>
>>
>> When submitting a CONST_IB, emit a SWITCH_BUFFER
>> packet before the CONST_IB. This isn't strictly necessary
>> (the driver will work fine without it), but is good practice
>> and allows for more flexible DE/CE sychronization options
>> in the future. Current userspace drivers do not take
>> advantage of the CE yet.
>>
>> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
>> ---
>> drivers/gpu/drm/radeon/si.c | 6 ++++++
>> drivers/gpu/drm/radeon/sid.h | 1 +
>> 2 files changed, 7 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
>> index 53e313b..191a3cd 100644
>> --- a/drivers/gpu/drm/radeon/si.c
>> +++ b/drivers/gpu/drm/radeon/si.c
>> @@ -1778,6 +1778,12 @@ void si_ring_ib_execute(struct radeon_device *rdev,
>> struct radeon_ib *ib)
>> else
>> header = PACKET3(PACKET3_INDIRECT_BUFFER, 2);
>> + if (ib->is_const_ib) {
>> + /* set switch buffer packet before const IB */
>> + radeon_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER,
>> 0));
>> + radeon_ring_write(ring, 0);
>> + }
>> +
>
> Additional to that I don't think the read cache flush and rptr saving is
> appropriate for a const IB, but on the other side I don't claim that I have
> understood the CE/DE separation fully yet.
Yeah, we could probably skip them for the const ib.
Alex
>
> Christian.
>
>
>> radeon_ring_write(ring, header);
>> radeon_ring_write(ring,
>> #ifdef __BIG_ENDIAN
>> diff --git a/drivers/gpu/drm/radeon/sid.h b/drivers/gpu/drm/radeon/sid.h
>> index db40679..7869089 100644
>> --- a/drivers/gpu/drm/radeon/sid.h
>> +++ b/drivers/gpu/drm/radeon/sid.h
>> @@ -901,5 +901,6 @@
>> #define PACKET3_WAIT_ON_DE_COUNTER_DIFF 0x88
>> #define PACKET3_SET_CE_DE_COUNTERS 0x89
>> #define PACKET3_WAIT_ON_AVAIL_BUFFER 0x8A
>> +#define PACKET3_SWITCH_BUFFER 0x8B
>> #endif
>
>
>
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