[Nouveau] [PATCH 4/5] gr/gf100: wait on bottom half of FE's pipeline

[Alexandre Courbot]

On Mon, Jun 8, 2015 at 8:04 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> A naive question from someone who knows nothing of icmd or bundles... Would
> it be better to wait for both bits to become 0 (I.e. 0x6)?

My understanding is that a method reaching the bottom half implies it
has passed to upper half (whatever these halfs are, I need to dig into
the doc to completely figure it out), and thus that while waiting for
both bits would do no harm, it would not do any good either.

Waiting on the bottom half is what downstream does, so I think this
behavior is safe to apply to Nouveau.

>
> On Jun 8, 2015 11:54 AM, "Alexandre Courbot" <acourbot at nvidia.com> wrote:
>>
>> When emitting the ICMD bundle, wait on the bottom half (bit 3 of the
>> GR_STATUS register) instead of upper half (bit 2) to make sure methods
>> are effectively emitted.
>>
>> Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
>> ---
>>  drm/nouveau/nvkm/engine/gr/gf100.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drm/nouveau/nvkm/engine/gr/gf100.c
>> b/drm/nouveau/nvkm/engine/gr/gf100.c
>> index 5606c25e5d02..01efc2c96045 100644
>> --- a/drm/nouveau/nvkm/engine/gr/gf100.c
>> +++ b/drm/nouveau/nvkm/engine/gr/gf100.c
>> @@ -699,7 +699,7 @@ gf100_gr_icmd(struct gf100_gr_priv *priv, const struct
>> gf100_gr_pack *p)
>>
>>                 while (addr < next) {
>>                         nv_wr32(priv, 0x400200, addr);
>> -                       nv_wait(priv, 0x400700, 0x00000002, 0x00000000);
>> +                       nv_wait(priv, 0x400700, 0x00000004, 0x00000000);
>>                         addr += init->pitch;
>>                 }
>>         }
>> --
>> 2.4.2
>>
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