[Mesa-dev] [PATCH 10/12] mesa: Use _mesa_lock_context_textures in _mesa_GetTexParameterfv()

[Kenneth Graunke]

On Monday, August 11, 2014 05:29:40 PM Kristian Høgsberg wrote:
> GetTexParamterfv() doesnt change texture state, so instead of
> _mesa_lock_texture() we can use _mesa_lock_context_textures(),
> which doesn't increase the texture stamp.  With this change,
> _mesa_update_state_locked() is now only called from under
> _mesa_lock_context_textures(), which is right thing to do.  Right now
> it's the same mutex, but if we made texture locking more fine grained
> locking one day, just locking one texture here would be wrong.
> 
> This all ignores the fact that texture locking seem a bit
> flaky and broken, but we're trying to not blatantly make it worse.
> 
> This change allows us to reliably unlock the context textures in the
> dd::UpdateState callback as is necessary for meta color resolves.
> 
> Signed-off-by: Kristian Høgsberg <krh at bitplanet.net>
> ---
>  src/mesa/main/texparam.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/src/mesa/main/texparam.c b/src/mesa/main/texparam.c
> index 30dd0b9..e40fb24 100644
> --- a/src/mesa/main/texparam.c
> +++ b/src/mesa/main/texparam.c
> @@ -1384,7 +1384,7 @@ _mesa_GetTexParameterfv( GLenum target, GLenum pname, GLfloat *params )
>     if (!obj)
>        return;
>  
> -   _mesa_lock_texture(ctx, obj);
> +   _mesa_lock_context_textures(ctx);
>     switch (pname) {
>        case GL_TEXTURE_MAG_FILTER:
>  	 *params = ENUM_TO_FLOAT(obj->Sampler.MagFilter);
> @@ -1591,11 +1591,11 @@ _mesa_GetTexParameterfv( GLenum target, GLenum pname, GLfloat *params )
>     }
>  
>     /* no error if we get here */
> -   _mesa_unlock_texture(ctx, obj);
> +   _mesa_unlock_context_textures(ctx);
>     return;
>  
>  invalid_pname:
> -   _mesa_unlock_texture(ctx, obj);
> +   _mesa_unlock_context_textures(ctx);
>     _mesa_error(ctx, GL_INVALID_ENUM, "glGetTexParameterfv(pname=0x%x)", pname);
>  }
>  
> 

Yeah...the old code incremented the texture timestamp, and I don't see any point in that.  It doesn't alter the state at all.  This patch retains taking the mutex.

But, it really seems like you need to do the analogous change in _mesa_GetTexParameteriv().  I think you'll hit the same issue, and are just getting lucky...

With that fixed,
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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