The Linux kernel's AMD display driver had a flaw where the dce110_set_avmute function called the is_tg_enabled operation unconditionally on timing generators. Older DCE timing generators do not implement this operation, leading to a NULL pointer dereference on Southern Islands discrete GPUs during HDMI display shutdown. The vulnerability was fixed by verifying that the timing generator and the required operations exist before waiting for AV mute frames, preventing the NULL pointer dereference.

This vulnerability could cause a NULL pointer dereference, resulting in a kernel crash or denial of service when turning off the display over HDMI on affected hardware. There is no indication of code execution or privilege escalation. No known exploits in the wild have been reported.

A fix has been applied in the Linux kernel to check for the presence of timing generator operations before calling them in dce110_set_avmute. Users should update to a Linux kernel version that includes this patch. Patch status is not explicitly confirmed in the provided data; check the vendor advisory or Linux kernel release notes for the exact fixed version.