[Intel-gfx] [PATCH] drm/i915: Return early when pipes are not available

[Chris Wilson]

Quoting Mika Kahola (2017-11-09 10:49:52)
> At least in Coffee Lake it happens that we start initiliazing audio when
> no display is connected. This was discovered by CI when running IGT test
> case
> 
> drv_module_reload --r basic-no-display
> 
> The issue here is that the 'intel_device_info_runtime_init()' sets
> num_pipes to 0 but before this happens the audio part has already started
> to initialize itself. Later on the num_pipes is updated to 0 in
> intel_device_info_runtime_init() and we hit that when audio part is digging
> out ELD. This causes a warning in dmesg. To fix this issue, let's check the
> number of available pipes when trying to read out ELD.

dev_info_runtime_init() is too late. It depends on mmio being enabled to
probe the HW and nothing else; so move it to i915_driver_init_mmio()?
-Chris