[Mesa-dev] [PATCH 1/7] gallium: fold u_trim_pipe_prim call from st/mesa to drivers

[Marek Olšák]

On Fri, Apr 14, 2017 at 6:47 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Fri, Apr 14, 2017 at 12:42 PM, Marek Olšák <maraeo at gmail.com> wrote:
>> On Fri, Apr 14, 2017 at 5:45 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>> On Fri, Apr 14, 2017 at 11:07 AM, Marek Olšák <maraeo at gmail.com> wrote:
>>>> diff --git a/src/gallium/drivers/nouveau/nv30/nv30_vbo.c b/src/gallium/drivers/nouveau/nv30/nv30_vbo.c
>>>> index bc9b9a1..295c394 100644
>>>> --- a/src/gallium/drivers/nouveau/nv30/nv30_vbo.c
>>>> +++ b/src/gallium/drivers/nouveau/nv30/nv30_vbo.c
>>>> @@ -543,20 +543,23 @@ nv30_draw_elements(struct nv30_context *nv30, bool shorten,
>>>>     }
>>>>  }
>>>>
>>>>  static void
>>>>  nv30_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info)
>>>>  {
>>>>     struct nv30_context *nv30 = nv30_context(pipe);
>>>>     struct nouveau_pushbuf *push = nv30->base.pushbuf;
>>>>     int i;
>>>>
>>>> +   if (!u_trim_pipe_prim(info->mode, (unsigned*)&info->count))
>>>> +      return;
>>>> +
>>>
>>> Should this also have a !info->primitive_restart? It's supported on
>>> nv4x (covered by this driver).
>>
>> In that case, I wonder if u_trim_pipe_prim is required with this
>> driver. It might be better to just remove that call.
>
> Based on a quick look, this seems to exist to prevent short draws and
> trim the count to the nearest prim size, i.e. if you try to draw a tri
> with %3 != 0 vertices, or a line with %2 != 0? I'm not 100% sure that
> the NV30 HW handles those correctly, but it probably does. I can
> double-check tonight, as I have one plugged in these days.

I'll just add this. Is it OK?

diff --git a/src/gallium/drivers/nouveau/nv30/nv30_vbo.c
b/src/gallium/drivers/nouveau/nv30/nv30_vbo.c
index 295c394..316f868 100644
--- a/src/gallium/drivers/nouveau/nv30/nv30_vbo.c
+++ b/src/gallium/drivers/nouveau/nv30/nv30_vbo.c
@@ -550,7 +550,8 @@ nv30_draw_vbo(struct pipe_context *pipe, const
struct pipe_draw_info *info)
    struct nouveau_pushbuf *push = nv30->base.pushbuf;
    int i;

-   if (!u_trim_pipe_prim(info->mode, (unsigned*)&info->count))
+   if (!info->primitive_restart &&
+       !u_trim_pipe_prim(info->mode, (unsigned*)&info->count))
       return;

    /* For picking only a few vertices from a large user buffer, push is better,

Marek