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

[Kahola, Mika]

> -----Original Message-----
> From: Hogander, Jouni <jouni.hogander at intel.com>
> Sent: Monday, October 24, 2022 8:47 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: Hogander, Jouni <jouni.hogander at intel.com>; Souza, Jose
> <jose.souza at intel.com>; Ville Syrjälä <ville.syrjala at linux.intel.com>; Kahola,
> Mika <mika.kahola at intel.com>; Brian J . Tarricone <brian at tarricone.org>
> Subject: [PATCH] drm/i915/psr: Send update also on invalidate
> 
> 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.
> 
> 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>

Looks like a valid call to do.

Reviewed-by: Mika Kahola <mika.kahola at intel.com>

> ---
>  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) |
> --
> 2.34.1