drm/i915: Don't explode when the dig port we don't have an AUX CH
commit 0b385be4 upstream. The icl+ power well code currently assumes that every AUX power well maps to an encoder which is using said power well. That is by no menas guaranteed as we: - only register encoders for ports declared in the VBT - combo PHY HDMI-only encoder no longer get an AUX CH since commit 9856308c ("drm/i915: Only populate aux_ch if really needed") However we have places such as intel_power_domains_sanitize_state() that blindly traverse all the possible power wells. So these bits of code may very well encounbter an aux power well with no associated encoder. In this particular case the BIOS seems to have left one AUX power well enabled even though we're dealing with a HDMI only encoder on a combo PHY. We then proceed to turn off said power well and explode when we can't find a matching encoder. As a short term fix we should be able to just skip the PHY related parts of the power well programming since we know this situation can only happen with combo PHYs. Another option might be to go back to always picking an AUX CH for all encoders. However I'm a bit wary about that since we might in theory end up conflicting with the VBT AUX CH assignment. Also that wouldn't help with encoders not declared in the VBT, should we ever need to poke the corresponding power wells. Longer term we need to figure out what the actual relationship is between the PHY vs. AUX CH vs. AUX power well. Currently this is entirely unclear. Cc: stable@vger.kernel.org Fixes: 9856308c ("drm/i915: Only populate aux_ch if really needed") Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10184 Signed-off-by:Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240223203216.15210-1-ville.syrjala@linux.intel.com Reviewed-by:
Imre Deak <imre.deak@intel.com> (cherry picked from commit 6a8c66bf ) Signed-off-by:
Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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