drm/i915: Switch over to gen3 irq code on gen2

The only real reason why we have the gen2 vs. gen3+ split
in irq handling is that bspec claims that IIR/IMR/IER/ISR
and EMR are only 16 bits on gen2, as opposed to being 32
bits on gen3+. That doesn't seem to be a meaningful
distinction as 32bit access to these registers works
perfectly fine on gen2

Interestingly the 16 msbs of IMR are in fact hardcoded
to 1 on gen2, which to me indicates that 32bit access
was the plan all along, and perhaps someone just forgot
to update the spec.

Nuke the special 16bit gen2 irq code and switch over to
the gen3 code.

Gen2 doesn't have the ASLE interrupt, which just needs
a small tweak in i915_irq_postinstall().

And so far we've not had a codepath that could enable the
legacy BLC interrupt on gen2. Now we do, but we'll never
actually do it since gen2 machines don't have OpRegion.
(and neither do i915/i945 machines btw). On these older
platforms the legacy BLC interrupt is meant to be used
in conjunction with the LBPC backlight stuff, but we
never actually switch off the legacy/combination mode
and thus don't use the interrupt either.

This was quickly smoke tested on all gen2 variants.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240927143545.8665-5-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

0 files changed, 0 insertions, 0 deletions