[Intel-gfx] [PATCH] drm/i915/psr: Send update also on invalidate

[Souza, Jose]

On Mon, 2022-10-24 at 08:46 +0300, Jouni Högander wrote:
> Currently we are observing mouse cursor stuttering when using
> xrandr --scaling=1.2x1.2. X scaling/transformation seems to be
> doing fronbuffer rendering. When moving mouse cursor X seems to
> perform several invalidates and only one DirtyFB. I.e. it seems
> to be assuming updates are sent to panel while drawing is done.
> 
> Earlier we were disabling PSR in frontbuffer invalidate call back
> (when drawing in X started). PSR was re-enabled in frontbuffer
> flush callback (dirtyfb ioctl). This was working fine with X
> scaling/transformation. Now we are just enabling continuous full
> frame (cff) in PSR invalidate callback. Enabling cff doesn't
> trigger any updates. It just configures PSR to send full frame
> when updates are sent. I.e. there are no updates on screen before
> PSR flush callback is made. X seems to be doing several updates
> in frontbuffer before doing dirtyfb ioctl.
> 
> Fix this by sending single update on every invalidate callback.

Fair enough.

Reviewed-by: José Roberto de Souza <jose.souza at intel.com>

> 
> Cc: José Roberto de Souza <jose.souza at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Mika Kahola <mika.kahola at intel.com>
> 
> Fixes: 805f04d42a6b ("drm/i915/display/psr: Use continuos full frame to handle frontbuffer invalidations")
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6679
> Signed-off-by: Jouni Högander <jouni.hogander at intel.com>
> Reported-by: Brian J. Tarricone <brian at tarricone.org>
> Tested-by: Brian J. Tarricone <brian at tarricone.org>
> ---
>  drivers/gpu/drm/i915/display/intel_psr.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> index 904a1049eff3..564d4fd94048 100644
> --- a/drivers/gpu/drm/i915/display/intel_psr.c
> +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> @@ -2209,8 +2209,11 @@ static void _psr_invalidate_handle(struct intel_dp *intel_dp)
>  	if (intel_dp->psr.psr2_sel_fetch_enabled) {
>  		u32 val;
>  
> -		if (intel_dp->psr.psr2_sel_fetch_cff_enabled)
> +		if (intel_dp->psr.psr2_sel_fetch_cff_enabled) {
> +			/* Send one update otherwise lag is observed in screen */
> +			intel_de_write(dev_priv, CURSURFLIVE(intel_dp->psr.pipe), 0);
>  			return;
> +		}
>  
>  		val = man_trk_ctl_enable_bit_get(dev_priv) |
>  		      man_trk_ctl_partial_frame_bit_get(dev_priv) |