Easy way to set that parameter: Run 'sudo xdiagnose', then in the GUI tick the first checkbox (Graphics debugging), exit, and reboot. Then collect your dmesg and it should have the required debug info.
Easy way to set that parameter: Run 'sudo xdiagnose', then in the GUI tick the first checkbox (Graphics debugging), exit, and reboot. Then collect your dmesg and it should have the required debug info.