[PATCH] drm: Don't oops in drm_calc_timestamping_constants() if drm_vblank_init() wasn't called

ase where vblank > support was initialized, but the wrong number of crtcs was specified. That was fast, thanks! Works for me. Tested-by: Jeff Moyer

NULL pointer deref at 0xb0, IP drm_calc_timestamping_constants+0x86/0x130 [drm]

Hi, I get the following BUG when booting the latest mainline kernel (as of commit 8d3de01cfa37b). objdump --disassemble -l points at this line in the code: drm_irq.c:644vblank->linedur_ns = linedur_ns; To further corroborate this, offset 0xb0 into struct drm_vblank_crtc is linedur_ns.