Re: [PATCH] drm/i915/alpm: ALPM disable fixes

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Feb 12, 2026 at 08:27:31AM +0200, Jouni Högander wrote:
> PORT_ALPM_CTL is supposed to be written only before link training. Remove
> writing it from ALPM disable.
> 
> Also clearing ALPM_CTL_ALPM_AUX_LESS_ENABLE and is not about disabling ALPM
> but switching to AUX-Wake ALPM. Stop touching this bit on ALPM disable.

There's another open coded variant of this in intel_alpm_lobf_disable(),
and that thing also gets passed the wrong crtc_state (new instead of
old).

Also LOBF enable is now being done from two places (intel_alpm_lobf_enable()
and intel_psr_enable_source()). How those two interact is anyone's guess.

> 
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/7153
> Fixes: 1ccbf135862b ("drm/i915/psr: Enable ALPM on source side for eDP Panel replay")
> Cc: Animesh Manna <animesh.manna@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: <stable@vger.kernel.org> # v6.10+
> Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_alpm.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c b/drivers/gpu/drm/i915/display/intel_alpm.c
> index e0a4a59dc025..b3334bc4d0f9 100644
> --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> @@ -604,12 +604,7 @@ void intel_alpm_disable(struct intel_dp *intel_dp)
>  	mutex_lock(&intel_dp->alpm.lock);
>  
>  	intel_de_rmw(display, ALPM_CTL(display, cpu_transcoder),
> -		     ALPM_CTL_ALPM_ENABLE | ALPM_CTL_LOBF_ENABLE |
> -		     ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
> -
> -	intel_de_rmw(display,
> -		     PORT_ALPM_CTL(cpu_transcoder),
> -		     PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE, 0);
> +		     ALPM_CTL_ALPM_ENABLE | ALPM_CTL_LOBF_ENABLE, 0);
>  
>  	drm_dbg_kms(display->drm, "Disabling ALPM\n");
>  	mutex_unlock(&intel_dp->alpm.lock);
> -- 
> 2.43.0

-- 
Ville Syrjälä
Intel