[Mesa-dev] [PATCH 2/3] egl: return corresponding offset of EGLImage instead of 0.

[Weng, Chuanbo]

Hi Axel and Emil,
	Thanks Axel for your review. Please see my comments below.

-----Original Message-----
From: Axel Davy [mailto:axel.davy at ens.fr] 
Sent: Friday, September 9, 2016 1:25 AM
To: Weng, Chuanbo <chuanbo.weng at intel.com>; mesa-dev at lists.freedesktop.org; emil.l.velikov at gmail.com
Subject: Re: [Mesa-dev] [PATCH 2/3] egl: return corresponding offset of EGLImage instead of 0.

Hi,

That doesn't seem good to me.

With that patch, that means that since no one is implementing

__DRI_IMAGE_ATTRIB_OFFSET

(yes I know in a later patch you implement it for i965),

then what used to work will stop working (as the queryImage will return false).

You need to introduce some interface version implementation check.
[****Chuanbo****] Maybe I can add more comment to git log (such as "This patch just implements egl loader side, the driver side 
implementation is also needed for corresponding platform"), so user can be aware of this.
Introduce interface version implementation check will make mesa code more complex, because we should also add related check to
other dri2 functions(dri2_****).
Another solution is combining the three patches into one patch, as I did before:
https://lists.freedesktop.org/archives/mesa-dev/2016-August/126945.html
This is not as easy as this version for reviewers, but more clearer for users.
Emil, what do you think?


(another nitpick: queryImage return true or false, not EGL_TRUE/EGL_FALSE. It's better to convert, instead of assuming they're the same)
[****Chuanbo****] Agree.

Yours,

Axel Davy

On 06/09/2016 11:06, Chuanbo Weng wrote:
> The offset should not always be 0. For example, if EGLImage is created 
> from a 2D texture with EGL_GL_TEXTURE_LEVEL=1, then the offset should 
> be the actual start of miplevel 1 in bo.
>
> Signed-off-by: Chuanbo Weng <chuanbo.weng at intel.com>
> ---
>   src/egl/drivers/dri2/egl_dri2.c | 12 +++++++++---
>   1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/src/egl/drivers/dri2/egl_dri2.c 
> b/src/egl/drivers/dri2/egl_dri2.c index 859612f..8ef0acd 100644
> --- a/src/egl/drivers/dri2/egl_dri2.c
> +++ b/src/egl/drivers/dri2/egl_dri2.c
> @@ -2249,6 +2249,8 @@ dri2_export_dma_buf_image_mesa(_EGLDriver *drv, _EGLDisplay *disp, _EGLImage *im
>      struct dri2_egl_image *dri2_img = dri2_egl_image(img);
>   
>      (void) drv;
> +   EGLBoolean ret = EGL_TRUE;
> +   EGLint img_offset = 0;
>   
>      /* rework later to provide multiple fds/strides/offsets */
>      if (fds)
> @@ -2259,10 +2261,14 @@ dri2_export_dma_buf_image_mesa(_EGLDriver *drv, _EGLDisplay *disp, _EGLImage *im
>         dri2_dpy->image->queryImage(dri2_img->dri_image,
>   				  __DRI_IMAGE_ATTRIB_STRIDE, strides);
>   
> -   if (offsets)
> -      offsets[0] = 0;
> +   if (offsets){
> +      ret = dri2_dpy->image->queryImage(dri2_img->dri_image,
> +				        __DRI_IMAGE_ATTRIB_OFFSET, &img_offset);
> +      if(ret == EGL_TRUE)
> +        offsets[0] = img_offset;
> +   }
>   
> -   return EGL_TRUE;
> +   return ret;
>   }
>   
>   #endif