[ICL] Trying to use non-existent 6th (F) DDI port

Submitted by Imre Deak @ideak

Assigned to Imre Deak @ideak

Link to original bug (#108915)

Description

Some ICL SKUs support only 5 DDI ports (2 combo-PHY and 3 MG PHY) instead of the maximum of 6 ICL supports. We need a way to detect these SKUs based either on VBT or the PCI ID and prevent using the non-existent port.

SKL-Y is one such system, where this problem results in the following error whenever trying to use the non-existent port F:

<7>[ 10.710403] [drm:intel_power_well_enable [i915]] enabling AUX F
<4>[ 10.711756] ------------[ cut here ]------------
<4>[ 10.711760] WARN_ON(intel_wait_for_register(dev_priv, regs->driver, (0x1 << ((pw_idx) * 2)), (0x1 << ((pw_idx) * 2)), 1))

One example:
https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_5234/fi-icl-y/boot0.log