egl/drm: Fix misused x and y offsets in swrast_get_image()

It fixes misused x and y variables on the calculation of the memory copy regions.

Cc: Giovanni Campagna <gcampagna@src.gnome.org>
Fixes: 8430af5ebe1ee8119e14 "Add support for swrast to the DRM EGL platform"
Signed-off-by: Mun Gwan-gyeong <elongbug@gmail.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

[Eric: use gbm_bo_get_bpp() instead of local function, split clamp patch]
Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>

1 files changed, 19 insertions, 4 deletions

diff --git a/src/egl/drivers/dri2/platform_drm.c b/src/egl/drivers/dri2/platform_drm.c
index b1cb3e13e6..a952aa5456 100644
--- a/src/egl/drivers/dri2/platform_drm.c
+++ b/src/egl/drivers/dri2/platform_drm.c
@@ -575,20 +575,35 @@ swrast_get_image(__DRIdrawable *driDrawable,
    struct dri2_egl_surface *dri2_surf = loaderPrivate;
    int internal_stride, stride;
    struct gbm_dri_bo *bo;
+   uint32_t bpp;
+   int x_bytes, width_bytes;
+   char *src, *dst;
 
    if (get_swrast_front_bo(dri2_surf) < 0)
       return;
 
    bo = gbm_dri_bo(dri2_surf->current->bo);
-   if (gbm_dri_bo_map_dumb(bo) == NULL)
+
+   bpp = gbm_bo_get_bpp(&bo->base);
+   if (bpp == 0)
       return;
 
+   x_bytes = x * (bpp >> 3);
+   width_bytes = width * (bpp >> 3);
+
    internal_stride = bo->base.stride;
-   stride = width * 4;
+   stride = width_bytes;
+
+   if (gbm_dri_bo_map_dumb(bo) == NULL)
+      return;
+
+   dst = data;
+   src = bo->map + x_bytes + (y * internal_stride);
 
    for (int i = 0; i < height; i++) {
-      memcpy(data + i * stride,
-             bo->map + (x + i) * internal_stride + y, stride);
+      memcpy(dst, src, width_bytes);
+      dst += stride;
+      src += internal_stride;
    }
 
    gbm_dri_bo_unmap_dumb(bo);