[igt-dev] [PATCH i-g-t 4/4] lib/igt_fb: Generalize the slow read from gtt mmap handling

[Chris Wilson]

Quoting Ville Syrjala (2018-11-02 19:06:51)
> +static void *convert_src_get(const struct fb_convert *cvt)
> +{
> +       void *buf;
> +
> +       if (!cvt->src.slow_reads)
> +               return cvt->src.ptr;
> +
> +       /*
> +        * Reading from the BO is awfully slow because of lack of read caching,
> +        * it's faster to copy the whole BO to a temporary buffer and convert
> +        * from there.
> +        */
> +       buf = malloc(cvt->src.fb->size);

if (!buf)
	return cvt->src.ptr;

> +       igt_memcpy_from_wc(buf, cvt->src.ptr, cvt->src.fb->size);
> +
> +       return buf;
> +}
> +
> +static void convert_src_put(const struct fb_convert *cvt,
> +                           void *src_buf)
> +{
> +       /*
> +        * Reading from the BO is awfully slow because of lack of read caching,
> +        * it's faster to copy the whole BO to a temporary buffer and convert
> +        * from there.
> +        */
> +       if (cvt->src.slow_reads)

	if (src_buf != cvt->src.ptr)

> +               free(src_buf);
> +}