The defio subsystem overwrites the method fb_osp->mmap. That method is stored in module's static data - and that means that if we have multiple diplaylink adapters, they will over write each other's method.
In order to avoid interference between multiple adapters, we copy the fb_ops structure to a device-local memory.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Cc: stable@vger.kernel.org
--- drivers/gpu/drm/udl/udl_fb.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
Index: linux-4.17-rc7/drivers/gpu/drm/udl/udl_fb.c =================================================================== --- linux-4.17-rc7.orig/drivers/gpu/drm/udl/udl_fb.c 2018-06-03 13:05:20.000000000 +0200 +++ linux-4.17-rc7/drivers/gpu/drm/udl/udl_fb.c 2018-06-03 13:08:03.000000000 +0200 @@ -34,6 +34,7 @@ module_param(fb_defio, int, S_IWUSR | S_ struct udl_fbdev { struct drm_fb_helper helper; struct udl_framebuffer ufb; + struct fb_ops fb_ops; int fb_count; };
@@ -405,7 +406,8 @@ static int udlfb_create(struct drm_fb_he info->fix.smem_len = size; info->fix.smem_start = (unsigned long)ufbdev->ufb.obj->vmapping;
- info->fbops = &udlfb_ops; + ufbdev->fb_ops = udlfb_ops; + info->fbops = &ufbdev->fb_ops; drm_fb_helper_fill_fix(info, fb->pitches[0], fb->format->depth); drm_fb_helper_fill_var(info, &ufbdev->helper, sizes->fb_width, sizes->fb_height);