Make life simpler by always programming DP M2/N2 with a consistent
value. This will lets use do state readout+chec unconditionally.
I was first going to just set M2/N2=M1/N1 but then it occurred
to me that it might interfere with fastboot on account of BIOS
likely leaving the registers zeroed. So let's zero out the values
instead (except TU where a zero register value actually means '1').
Still not sure that's the best approach but lets go with it for
now.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220128103757.22461-14-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Currently we allow DRRS on IVB PCH ports, but we're missing a
few programming steps meaning it is guaranteed to not work.
And on HSW DRRS is not supported on anything but port A ever
as only transcoder EDP has the M2/N2 registers (though I'm
not sure if HSW ever has eDP on any other port).
Starting from BDW all transcoders have the dynamically
reprogrammable M/N registers so DRRS could work on any
port.
Stop initializing DRRS on ports where it cannot possibly work.
Cc: stable@vger.kernel.org
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220128103757.22461-11-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Make things a bit more explicit by splitting
intel_cpu_transcoder_set_m_n() into separate variants for M1/N1 vs.
M2/N2. Makes the DRRS M/N programming at least more obvious.
Note that for the MST and DRRS cases we don't need to call the
M2/N2 variant at all since the transcoders that support those
do not have the M2/N2 registers.
Same could be said for i9xx_crtc_enable() but I want to do a
higher level code sharing between that valleyview_crtc_enable()
later in which case we do need the M2/N2 variant. This is also
why I keep the transcoder_has_m2_n2() in intel_cpu_transcoder_set_m2_n2()
so the caller doesn't have necessarily care what the chosen
transcoder supports.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220128103757.22461-5-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Frontbuffer rendering will be dropped for modern platforms but
before that we to prepare DRRS for it.
intel_drrs_flush and intel_drrs_invalidate will not be called
for platforms that will not support frontbuffer rendering so DRRS
needs another way to be notified about to page flips so it can change
between high and low refresh rates as needed.
Reviewed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210903221036.34770-3-jose.souza@intel.com
