Atomicity in KMS panic notifier

Hi,

while debugging a few reported bugs, I noticed that drm_fb_helper_force_kernel_mode() that is called in the KMS panic notifier isn't really atomic-safe. It invokes crtc's set_config(), and all implementations seem to involve with page allocations (kmalloc with GFP_KERNEL, via some ttm ops, etc). I've actually seen the Oops with cirrus KMS during panic due to this.

Does anyone have an idea to fix this? I thought of re-using drm_fb_helper_debug_enter(), but this won't work with many drivers that don't have crtc->mode_set_base_atomic(), either (yeah, this is another bug).

thanks,

Takashi