Hi,
In Exynos DRM driver I found a NULL pointer exception when there were no components set for DRM driver: https://lkml.org/lkml/2014/6/30/331
The NULL pointer will happen during driver suspend if drm_driver.load() is not called. The load() won't be called if no components are added.
After looking at other DRM drivers it seems that they may also be affected by this issue. Some possible candidates (for my amateur's eyes) are: 1. vmwgfx/vmwgfx_drv.c (vmw_pci_suspend: dereference of 'dev_priv') 2. qxl/qxl_drv.c (qxl_drm_freeze: dereference of 'qdev') 3. nouveau/nouveau_drm.c (nouveau_do_suspend: dereference of 'drm') 4. msm/msm_drv.c (msm_pm_suspend: dereference of 'ddev') 5. cirrus/cirrus_drv.c (cirrus_pm_suspend: dereference of 'cdev') 6. bochs/bochs_drv.c (bochs_pm_suspend: dereference of 'bochs')
Unfortunately I am not familiar with DRM drivers and I do not have hardware to test it.
Maybe it is worth looking at?
Best regards, Krzysztof