Potential NULL pointer dereference in atombios_get_encoder_mode

[Shaobo He]

Hello everyone,

My name is Shaobo He and I am a graduate student at University of Utah. I am 
using a static analysis tool to search for null pointer dereferences and came 
across a potentially invalid memory accesses in the file 
drivers/gpu/drm/radeon/atombios_encoders.c: in function 
`atombios_get_encoder_mode`, function `radeon_get_connector_for_encoder_init` 
can return a NULL pointer. It seems the only chance that it may happen is that 
there is not any connector attached to the device of the encoder or connectors 
are all invalid. I was wondering if it can happen in the call context.

Please let me know if it makes sense. I am looking forward to your reply.

Best,
Shaobo